Fluid testing chip and cassette

ABSTRACT

A fluid testing cassette may comprise a microfluidic channel having a constriction and a micro-fabricated integrated sensor within the constriction. In one implementation, the constriction is less than or equal to 30 μm. In one implementation, the cassette further comprises a nozzle connecting the microfluidic channel to the discharge reservoir, wherein a thermal resistor expels fluid within the microfluidic channel into the discharge reservoir.

BACKGROUND

Various different sensing devices are currently available for sensingdifferent attributes of fluid, such as blood as an example. Such sensingdevices are often large, complex and expensive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an example microfluidic diagnostictesting chip.

FIG. 2 is a sectional view schematically illustrating another examplemicrofluidic diagnostic testing chip.

FIG. 3 is a sectional view schematically illustrating another examplemicrofluidic diagnostic testing chip.

FIG. 4 is a schematic diagram of another example microfluidic diagnostictesting chip.

FIG. 5 is a schematic diagram of an example fluid testing systemcomprising another example microfluidic diagnostic chip.

FIG. 6 is a schematic diagram of an example microfluidic channel inwhich are disposed an example fluid pump and sensors.

FIG. 7 is a schematic diagram of another example fluid testing system.

FIG. 8 is a perspective view of an example cassette.

FIG. 9A is a sectional view of the cassette of FIG. 8 with a modifiedexterior.

FIG. 9B is a perspective view of the cassette of FIG. 9A with portionsomitted or shown transparently.

FIG. 9C is a top view of the cassette of FIG. 9A with portions omittedor shown transparently.

FIG. 10A is a top view of an example cassette board supporting anexample microfluidic cassette and funnel.

FIG. 10B is a bottom view of the cassette board of FIG. 10A.

FIG. 11 is a fragmentary sectional view of a portion of the cassetteboard of FIG. 10A.

FIG. 12 is a top view of another example of the microfluidic chip of thecassette of FIGS. 8 and 9A.

FIG. 13 is an enlarged fragmentary top view of an example sensing regionof the microfluidic chip of FIG. 12.

FIG. 14 is a fragmentary top view of an example microfluidic chip,illustrating an example electric sensor within an example microfluidicchannel.

FIG. 15 is a diagram illustrating a volume of an example constriction ofa microfluidic channel relative to an example cell.

FIG. 16 is a diagram of an example microfluidic channel comprising anexample electric sensor, illustrating the creation of an electric fieldand the relative size of the cell about to pass through the electricfield.

FIG. 17 is a fragmentary top view of another example microfluidic chipusable in the cassette of FIGS. 8 and 9A.

FIG. 18 is a fragmentary top view of another example microfluidic chipusable in the cassette of FIGS. 8 and 9A, illustrating examplemicrofluidic channel portions.

FIG. 19 is a fragmentary top view of the microfluidic chip of FIG. 18illustrating example pumps and sensors within the microfluidic channelportions.

FIG. 20 is a fragmentary top view of another example microfluidic chipusable in the cassette of FIGS. 8 and 9A.

FIG. 21 is a schematic diagram of an example impedance sensing circuit.

FIG. 22 is a diagram illustrating an example multi-threading methodcarried out by the fluid testing system of FIG. 7.

DETAILED DESCRIPTION OF EXAMPLES

FIG. 1 schematically illustrates an example microfluidic diagnostictesting chip 30. As will be described hereafter, chip 30 comprises achip having integrated micro-electromechanical systems and microfluidicsthat facilitate testing or diagnostics of a fluid on a chip or singledie. As a result, a fluid test may be performed with a much smalleramount of fluid and smaller amount of reagent, producing less waste andpotentially less bio-hazardous materials than current benchtop methodsfor fluid testing.

Chip 30 comprises a substrate 32 in which is formed a microfluidicreservoir 34, a microfluidic channel 36 and a micro-fabricatedintegrated sensor 38. Substrate 32 comprises a foundational structure orbase. In the example illustrated, substrate 32 comprises silicon. Inother implementations, substrate 32 is formed from other materials.

Microfluidic reservoir 34 comprises a cavity, chamber or volume in whichfluid on liquid, such as blood, is received and contained until beingdrawn into channel 36. In one implementation, reservoir 34 receives afluid from a larger reservoir provided as part of a cassette in whichchip 30 is supported.

Microfluidic channel 36 comprises a fluidic channel formed withinsubstrate 32 and extending from reservoir 34. As schematically shown bybroken lines in FIG. 1, microfluidic channel 36 may guide the flow offluid or direct fluid to various locations in different implementations.As indicated by broken arrow 50, in one implementation, channel 36directs fluid back to the reservoir 34 for circulating fluid. Asindicated by broken arrow 46, in another implementation, microfluidicchannel 36 directs fluid back to a discharge reservoir 48. As indicatedby broken arrow 44, in yet another implementation, channel 36 extends toother fluid destinations.

Microfluidic channel 36 comprises a constriction 40 through which fluidflows. For purposes of this disclosure, a “constriction” means anynarrowing in at least one dimension. A “constriction” may be formed by(A) one side of a channel having a protruberance projecting towards theother side of the channel, (B) both sides of a channel having at leastone protruberance projecting towards the other side of the channel,wherein such multiple protruberances are either aligned with one anotheror are staggered along the channel or (C) at least one column or pillarprojecting between two walls of the channel to discriminate against whatcan or cannot flow through the channel. In one implementation,constriction 40 comprises a region of channel 36 that has a smallercross-sectional area than both adjacent regions of channel 36, upstreamand downstream of constriction 40. Constriction 40 has a cross-sectionalarea similar to that of the individual particles or cells that passthrough constriction 40 and which are being tested. In oneimplementation in which the cells being tested have a general or averagemaximum data mention of 6 μm, constriction 40 has a cross-sectional areaof 100 μm². In one implementation, constriction 40 has a sensing volumeof 1000 μm³. For example, in one implementation, constriction 40 has asense volume form bioregion having a length of 10 μm, a width of 10 μmand a height of 10 μm. In one implementation, constriction 40 has awidth of no greater than 30 μm. The sizing or dimensioning ofconstriction 40 restricts the number of particles or individual cellsthat may pass through constriction 40 at any one moment, facilitatingtesting of individual cells or particles passing through constriction40.

Micro-fabricated integrated sensor 38 comprises a micro-fabricateddevice formed upon substrate 32 within constriction 40. In oneimplementation, sensor 38 comprises a micro-device that is designed tooutput electrical signals or cause changes in electrical signals thatindicate properties, parameters or characteristics of the fluid and/orcells/particles of the fluid passing through constriction 40. In oneimplementation, sensor 38 comprises an impedance sensor which outputssignals based upon changes in electrical impedance brought about bydifferently sized particles or cells flowing through constriction 40 andimpacting impedance of the electrical field across or withinconstriction 40. In one implementation, sensor 38 comprises anelectrically charged high side electrode and a low side electrode formedwithin or integrated within a surface of channel 36 within constriction40. In one implementation, the low side electrode is electricallygrounded. In another implementation, the low side electorate is afloating low side electrode.

FIG. 2 is a sectional view schematically illustrating an example fluiddiagnostic or testing cassette 110. Cassette 110 comprises a unit thatis to be releasably connected to a portable electronic device, eitherdirectly or indirectly via an intermediate interface device or multipleintermediate interface devices. Cassette 110 comprises cassette body112, microfluidic chip 130 and electrical connector 152.

Cassette body 112 supports microfluidic chip 130 and electricalconnector 152. In the example illustrated, cassette body 112 comprisessample input port and passage 154 and discharge reservoir 156. Sampleinput port and passage 154 comprises a fluid receiving chamber cavity toreceive fluid samples to be tested. Sample input port and passage 154directs receive fluid to microfluidic chip 130 for testing. In oneimplementation, sample input port and passage 154 faces upwardly and hasan open mouth through which droplets of fluid are deposited or drawn(through capillary action) into reservoir 154. In anotherimplementation, sample input port and passage 154 comprises a membranethrough which a needle may be inserted to inject the fluid being testedinto reservoir 154. In one implementation, sample input port and passage154 has a volume of at least 10 μL and less than or equal to 1000 μL inother implementations, sample input port and passage 154 may have othercapacities.

Discharge reservoir 156 comprises a cavity or chamber within body 112arranged to receive fluid discharged from chip 130. In oneimplementation, discharge reservoir 156 has a minimum volume of 10 μL.Discharge reservoir 156 contains fluid has been passed through chip 130and that has been processed or tested. In the example illustrated,discharge reservoir 156 extends below microfluidic chip 130 on anopposite side of microfluidic chip 130 as sample input port 154 suchthat microfluidic chip 130 is sandwiched between sample input port 154and discharge reservoir 156. Discharge reservoir 156 receives processedor tested fluid such that, the same fluid is not, tested multiple times.In one implementation, discharge reservoir 156 is completely containedwithin body 112 and is inaccessible (but through the destruction of body112 such as by cutting, drilling or other permanent structures arebreaking of body 112), locking the processed or tested fluid within body112 for storage or subsequent sanitary disposal along with disposal ofcassette 110. In yet another implementation, discharge reservoir 156 isaccessible through a door or septum 158 (schematically shown in brokenlines), allowing processed or tested fluid to be withdrawn fromreservoir 156 for further analysis of the tested fluid, for storage ofthe tested fluid in a separate container or for emptying of reservoir156 to facilitate continued use of cassette 110.

Microfluidic chip 130 is similar to microfluidic chip 30 (describedabove) except that microfluidic chip 130 is illustrated as specificallyadditionally comprising pump 160 and discharge passage 162. Thoseremaining components or elements of microfluidic chip 130 whichcorrespond to components of microfluidic chip 30 are numbered similarly.Pump 160 comprises a device to move fluid through microfluidic channel36 and through constriction 40 across sensor 38. Pump 160 draws fluidfrom microfluidic reservoir 34 into channel 36. Pump 160 further forcesor expels fluid that has passed through constriction 40, across sensor38, into discharge reservoir 156 through discharge passage 162.

In one implementation, pump 160 comprises a thermal resistor, whereinpulses of electrical current passing through the thermal resistor causesthermal resistor to produce heat, heating adjacent fluid to atemperature above a nucleation energy of the adjacent fluid to create avapor bubble which forcefully expels fluid through discharge passage 162into discharge reservoir 156. Upon collapse of the bubble, negativepressure draws fluid from microfluidic reservoir 34 into channel 36 andacross constriction 40 and sensor 38 to occupy the prior volume of thecollapsed bubble.

In yet other implementations, pump 160 may comprise other pumpingdevices. For example, in other implementations, pump 160 may comprise apiezo-resistive device that changes shape or vibrates in response toapplied electrical current to move a diaphragm to thereby move adjacentfluid through discharge passage 162 into discharge reservoir 156. In yetother implementations, pump 160 may comprise other microfluidic pumpingdevices in fluid communication with microfluidic channel 36 anddischarge passage 162.

Discharge passage 162 extends from pump 160 to discharge reservoir 156.Discharge passage 162 inhibits reverse floor backflow of fluid withindischarge reservoir back into pump 160 or channel 36. In oneimplementation, discharge passage 162 comprises a nozzle through whichfluid is pumped by pump 160 into discharge reservoir 156. In anotherimplementation, discharge passage 162 comprises a unidirectional valve.

Electrical connector 152 comprises a device by which microfluidiccassette 110 is releasably electrically connected directly or indirectlyto a portable electronic device. In one implementation, the electricconnection provided by electrical connector 152 facilitates transmissionof electrical power for powering components of microfluidic chip 130. Inone implementation, the electric connection provided by electricalconnector 152 facilitates transmission of electrical power in the formof electrical signals providing data transmission to microfluidic chip130 to facilitate control of components of microfluidic chip 130. In oneimplementation, electric connection provided by electrical connector 152facilitates transmission of electrical power in the form electricalsignals to facilitate the transmission of data from microfluidic chip130 to the portable electronic device, such as the transmission ofsignals from sensor 138 or other sensors. In one implementation,electrical connector 152 facilitates each of the powering ofmicrofluidic chip 130 as well as the transmission of data signals to andfrom microfluidic chip 130.

In the example illustrated, electrical connector 152 comprises aplurality of electrical contact pads which make contact withcorresponding pads of either the portable electronic device or anintermediate connection interface or device. In yet anotherimplementation, electrical connector 152 comprises a plurality ofelectrical prongs or pins, a plurality of electrical pin or prongreceptacles, or a combination of both. In the example illustrated,electrical connector 152 is electrically connected to components ofmicrofluidic chip 130 via electrical traces formed within or uponcassette body 112 or formed upon or within a flexible circuit secured tocassette body 112.

Electrical connector 152 facilitates releasable electrical connection toa portable electronic device such that microfluidic cassette 110 may beseparated from the portable electronic device, facilitating disposal orstorage of microfluidic cassette 110 with the analyzed fluid, such asblood, contained within discharge reservoir 156. As a result,microfluidic cassette 110, once used, may be exchanged with an unusedmicrofluidic cassette 110; the unused microfluidic cassette 110 beingconnected to the portable electronic device. Electrical connector 152provides modularization, allowing the portable electronic device andassociated fluid analytical circuitry to be repeatedly reused while thecassette 110 is separated for storage or disposal.

FIG. 3 is a schematic sectional view of microfluidic cassette 210,another example implementation of microfluidic cassette 110.Microfluidic cassette 210 is similar to microfluidic cassette 110 exceptthat microfluidic cassette 210 additionally comprises residence passage263, fluid reagent 264, membrane 266 and packaging 268. Those remainingelements of cassette 210 which correspond to cassette 110 are numberedsimilarly.

Residence passage 263 (schematically shown) comprises a fluid channel,conduit, tube or other passage extending between sample input port 154and microfluidic reservoir 34. Residence passage 263 extends betweensample input port 154 and microfluidic reservoir 34 in a tortuousfashion, an indirect or non-linear fashion full of twists and turns, tolengthen the time for a received sample, input through sample input port154, to travel or flow to microfluidic reservoir 34. Residence passage263 provides a volume in which the fluid sample being tested and fluidreagent 264 mix prior to reaching reservoir 34. In one implementation,residence passage 263 is circuitous, comprising a circular or helicalpassage winding in the space of cassette body 112 between inputreservoir 154 and microfluidic reservoir 34. In another implementation,residence passage 263 twists and turns, zigzags, snakes, serpentinesand/or meanders in a zigzag fashion within the space between sampleinput port 154 and microfluidic reservoir 34.

Fluid reagent 264 comprises a composition that interacts with the fluidto be tested, enhancing the ability of microfluidic chip 130 to analyzea selected characteristics or a group of selected characteristics of thefluid to be tested. In one implementation, fluid reagent 264 comprises acomposition to dilute the fluid being tested. In one implementation,fluid reagent 264 comprises a composition to perform lysis on the fluidbeing tested. In yet another implementation, fluid reagent 264 comprisesa composition to facilitate tagging of selected portions of the fluidbeing tested. For example, in one of limitation, fluid reagent 264comprises magnetic beads, gold beads or latex beads. In otherimplementations, fluid reagent 264 comprises other liquid or solidcompositions or liquids, distinct from the sample fluid to be tested,that interact with or that modify the sample fluid placed within sampleinput port 154 prior to the sample fluid being received, processed andanalyzed by microfluidic chip 130.

In the example illustrated, fluid reagent 264 is contained within sampleinput port 154 and/or residence passage 263 prior to insertion of thesample of fluid to be tested into sample input port 154. In the exampleillustrated, membrane 266 extends completely across a mouth of sampleinput port 154 so as to seal or contain fluid reagent 264 within sampleinput port 154 at least until the fluid sample is deposited with beensample input port 154. As a result, fluid reagent 264 may be prepackagedas part of cassette 110, ready for use with the subsequent deposits ofthe fluid sample to be tested. For example, a first cassette 110containing a first fluid reagent 264 may be predesigned for testing afirst characteristic of a first sample of fluid while a second cassette110 containing a second fluid reagent 264, different than the firstfluid reagent 264, may be predesigned for testing a secondcharacteristic of a second sample of fluid. In other words, differentcassettes 110 may be specifically designed for testing differentcharacteristics depending upon the type or a quantity of fluid reagent264 contained therein.

As indicated by broken lines 269, in one implementation, membrane 266comprise a panel or film that is secured completely about and over themouth of reservoir 154 by a pressure sensitive adhesive or otheradhesive so as to allow membrane 266 to be peeled away from the mouth ofreservoir 154, allowing the fluid sample to be deposited withinreservoir 154 and mixed with the fluid sample. In anotherimplementation, fluid reagent 264 is sealed or contained withinreservoir 154 by a panel or door that is slid open, pivoted to an openstate or torn away along a perforation or tear line. In each of theaforementioned implementations, because the fluid reagent 264 is sealedor contained within cassette 210 prior to use of cassette 210, cassette210 may be manufactured, inventoried and sold or distributed as aself-contained unit including both microfluidic chip 130 and the fluidreagent 264.

In the example illustrated, microfluidic cassette 210 comprises asupplemental fluid reagent source 270. Supplemental fluid reagent source270 supplies and additional mount of fluid reagent to sample input port154 as selected by the user of cassette 210. In the example illustrated,supplemental fluid reagent source 270 comprises a side chamber 272containing fluid reagent 274. Side chamber 272 is bordered by a flexiblediaphragm 276 which is manually depressed double by the finger orfingers of a user to depress and squeeze reagent 274 into reservoir 154.Aston said squeezing, reagent 274 remains within side chamber 272. Inone implementation, fluid reagent 274 is the same as fluid reagent 264.In another implementation, fluid reagent 274 comprises a different fluidreagent as compared to reagent 264. In yet other implementations, fluidreagent 264 is omitted, wherein a sample fluid may be deposited intoreservoir 154 and tested without any reagent or, alternatively, fluidreagent 274 may be selectively added to the fluid sample. In anotherimplementation, cassette 210 comprises multiple supplemental fluidreagent sources alongside reservoir 154, each of the multiplesupplemental fluid reagent sources containing a different fluid reagentand allowing a user to selectively deposit the associated fluid reagentinto reservoir 154 for mixing with the fluid sample. For example,cassette body 112 may comprise multiple side chambers 272 with multipledepressable or squeezable membranes 276 to selectively squeeze anassociated fluid reagent into reservoir 154. In still otherimplementations, supplemental fluid reagent source 270 is omitted.

Packaging 268 comprises a film, wrap, membrane or other panel ofmaterial enveloping, surrounding or containing microfluidic cassette210. Packaging 268 isolates cassette 210 and the contained fluid reagent264, 274 from the outside environment exterior to packaging 268. In oneimplementation, packaging 268 comprises a film to be torn or severed forremoval of cassette body 112 for insertion of our deposition of thefluid sample to be tested. Packaging 268 facilitates cassette 210 beingpre-manufactured and inventoried as a self-contained unit containing afluid reagent or multiple fluid reagents. Packaging 268 furtherindicates any tampering or prior use of cassette 210, assisting in theaccuracy of the testing results. In implementations where packaging 268is provided, membrane 266 may be omitted. In some implementations inwhich membrane 266 is provided, backing 268 may be omitted. In otherimplementations, cassette 210 comprises both membrane 266 and packaging268.

FIG. 4 schematically illustrates microfluidic chip 330, anotherimplementation of microfluidic chip 30. Microfluidic chip 330 is similarto microfluidic chip 30 except that microfluidic chip 330 isspecifically illustrated as circulating fluid that has been processed ortested back to microfluidic reservoir 34. Those elements or componentsof microfluidic chip 330 which correspond to components or elements ofmicrofluidic chip 30 are numbered similarly.

Microfluidic chip 330 illustrates two example circulation architectures332, 334 on opposite sides of reservoir 34 in substrate 32. Circulationarchitecture 332 comprises a microfluidic channel 336, sensors 338 andpump 360. Microfluidic channel 336 comprises a passage extending withinor formed within substrate 32 for the flow of a fluid sample. Channel336 comprises a pump containing central portion 362 and a pair of sensorcontaining branch portions 364, 366. Central portion 362 extends fromreservoir 34 and contains pump 360.

Sensor containing branch portions 364, 366 stem or branch off ofopposite sides of central portion 362 and extend back to reservoir 34.Each of branch portions 364, 366 comprises a constriction 40 a, 40 b, 40c (described above) through with the fluid flows. In one implementation,branch portions 364, 366 are similar to one another. In anotherimplementation, branch portions are shaped or dimensions different fromone another so as to facilitate different fluid flow characteristics.For example, the constrictions 40 or other regions of portions 364, 366may be differently sized such that particles or cell so a first sizemore readily flow through, if at ail, through one of portions 364, 366as compared to the other of portions 364, 366. Because portions 364, 366diverge from opposite sides of central portion 362, both of portions364, 366 receive fluid directly from portion 362 without fluid beingsiphoned to any other portions beforehand.

Pump 360 comprises a device to move fluid through microfluidic channel36 and through constrictions 40 across one of sensors 38. Pump 360 drawsfluid from microfluidic reservoir 34 into channel 336. Pump 360 furthercirculates fluid that has passed through constriction 40 and acrosssensor 38 back to reservoir 34.

In one implementation, pump 360 comprises a thermal resistor, whereinpulses of electrical current passing through the thermal resistor causesthermal resistor to produce heat, heating adjacent fluid to atemperature above a nucleation energy of the adjacent fluid to create avapor bubble which forcefully expels fluid across constrictions 40 andback into reservoir 34. Upon collapse of the bubble, negative pressuredraws fluid from microfluidic reservoir 34 into channel 336 to occupythe prior volume of the collapsed bubble.

In yet other implementations, pump 360 may comprise other pumpingdevices. For example, in other implementations, pump 360 may comprise apiezoresistive device that changes shape or vibrates in response toapplied electrical current to move a diaphragm to thereby move adjacentfluid across constrictions 40 and back to reservoir 34. In yet otherimplementations, pump 360 may comprise other microfluidic pumpingdevices in fluid communication with microfluidic channel 336.

Circulation architecture 334 comprises a microfluidic channel 376,sensors 378 and pump 380. Microfluidic channel 376 comprises a passageextending within or formed within substrate 32 for the flow of a fluidsample. Channel 376 comprises a pump containing end portion 382 and aseries of sensor containing branch portions 384, 386, 388. End portion382 extends from reservoir 34 and contains pump 380.

Sensor containing branch portions 384, 386, 388 stem or branch off ofend portion 382 and extend back to reservoir 34. Each of branch portions384, 386, 388 comprises a constriction 40 (described above) through withthe fluid flows. In the example illustrated, branch portions are shapedor dimensioned different from one another so as to facilitate differentfluid flow characteristics. For example, the constrictions 40 or otherregions of portions 384, 386, 388 may be differently sized such thatparticles or cell so a first size more readily flow through, if at all,through one of portions 384, 386, 388 as compared to the other ofportions 384, 386, 388. Because portions 384, 386, 388 are arranged aseries on one side of end portion 382, fluid being tested seriallypasses by or across each of portions 384, 386, 388 until such fluid ispermitted to pass through one of portions 384, 386, 388. For example, inone implementation which constriction 40 of portion 386 is larger thanconstriction 40 of portion 384 and which constriction 40 of portion 388is larger than constriction 40 of portion 386, smaller particles orcells are first siphoned off across portion 384 while the largerparticular cells continue past portion 34 until they reach the portion386, 388 that permits a passage back to reservoir 34. Those particles orcells that are too large for constriction 40 of portion 386 continue onto portion 388 where the particles or cells pass back to reservoir 34.As a result, different portions of the sample of fluid being tested areselectively drawn off or siphoned off for testing by different types ofsensors in the different portions 384-388. In another implementation,branch portions 384, 386, 388 are similar to one another.

Pump 380 is similar to pump 360 and comprises a device to move fluidthrough microfluidic channel 376 and through constriction 40 across oneof sensors. Pump 380 draws fluid from microfluidic reservoir 34 intochannel 376. Pump 380 further circulates fluid that has passed throughconstriction 40, across one of sensors 378, back to reservoir 34.

In one implementation, pump 380 comprises a thermal resistor, whereinpulses of electrical current passing through the thermal resistor causesthermal resistor to produce heat, heating adjacent fluid to atemperature above a nucleation energy of the adjacent fluid to create avapor bubble which forcefully moves fluid through constrictions 40 toreservoir 34. Upon collapse of the bubble, negative pressure draws fluidfrom microfluidic reservoir 34 into channel 376 to occupy the priorvolume of the collapsed bubble.

In yet other implementations, pump 380 may comprise other pumpingdevices. For example, in other implementations, pump 380 may comprise apiezoresistive device that changes shape or vibrates in response toapplied electrical current to move a diaphragm to thereby move adjacentfluid through constrictions 40 and back to reservoir 34. In yet otherimplementations, pump 380 may comprise other microfluidic pumpingdevices in fluid communication with microfluidic channel 376.

FIG. 5 schematically illustrates an example fluid testing system 400.Fluid testing system 400 comprises microfluidic chip 430 and portableelectronic device 432. Microfluidic chip 430 comprises substrate 32,microfluidic reservoir 34, microfluidic channels 336, 436, pumps 360,460, discharge passage 462, sensors 338, sensors 438, temperaturesensors 440, electrical connectors 152 and multiplexor circuitry 444.Substrate 32, reservoir 34, channel 336, pump 360, sensors 338 andelectrical connectors 152 are described above. Microfluidic channel 436comprises a fluidic channel or passage formed within substrate 32 andextending from reservoir 34 to discharge passage 460. In the exampleillustrated, microfluidic channel 436 comprises a plurality of inletportions 450 extending from distinct spaced locations along reservoir 34to discharge passage 462. Each of inlet portions 450 comprises aconstriction 40 in which one of sensors 438 is located. In oneimplementation, the constrictions 40 of each of inlet portions 450 aredifferently sized or have different cross-sectional areas to permitcells or particles of different sizes to flow into and pass through suchdifferently sized constrictions 40. For example, a first sized particleor cell may flow through the first one of inlet portions 450, but may beinhibited from flowing through the other of inlet portions 450 due tothe smaller size of the constrictions 40 of the other inlet portions450. Likewise, a second sized particle or cell and, smaller than thefirst sized particle or cell, may flow through the first one of theinlet ports 450 or a second one of the inlet portions 450, but may beinhibited from flowing through the other of the inlet portions 450.

Pump 460 is similar to pump 160 described above. Likewise, dischargepassage 462 is similar to discharge passage 162 described above. Pump460 comprises a device to move fluid through microfluidic channel 436and through constrictions 40 across sensors 438. Pump 460 draws fluidfrom microfluidic reservoir 34 into channel 436. Pump 460 further forcesor expels fluid that has passed through constriction 40, across one ofsensors 438, into a discharge reservoir 156 (described above) throughdischarge passage 462.

In one implementation, pump 460 comprises a thermal resistor, whereinpulses of electrical current passing through the thermal resistor causesthermal resistor to produce heat, heating adjacent fluid to atemperature above a nucleation energy of the adjacent fluid to create avapor bubble which forcefully expels fluid through discharge passage 462into discharge reservoir 156. Upon collapse of the bubble, negativepressure draws fluid from microfluidic reservoir 34 into channel 436 andacross constrictions 40 and sensors 38 to occupy the prior volume of thecollapsed bubble.

In yet other implementations, pump 460 may comprise other pumpingdevices. For example, in other implementations, pump 460 may comprise apiezoresistive device that changes shape or vibrates in response toapplied electrical current to move a diaphragm to thereby move adjacentfluid through discharge passage 462 into discharge reservoir 156. In yetother implementations, pump 460 may comprise other microfluidic pumpingdevices in fluid communication with microfluidic channel 36 anddischarge passage 462.

Discharge passage 462 extends from pump 460 to discharge reservoir 156.Discharge passage 462 inhibits reverse floor backflow of fluid withindischarge reservoir back into pump 460 or channel 436. In oneimplementation, discharge passage 462 comprises a nozzle through whichfluid is pumped by pump 460 into discharge reservoir 156. In anotherimplementation, discharge passage 462 comprises a unidirectional valve.

Sensors 438 are similar to sensors 38, 138, 338 described above. Sensors438 are located within constrictions to sense cells, particles or othercomponents of the sample fluid being tested as it passes through theassociated constriction 40. In one implementation, each of portions 450contains a different type of sensor such object a distinct property orcharacteristic of the fluid sample passing through the associatedconstriction 40. In one implementation, each of sensors 438 comprises animpedance sensor which outputs signals based upon changes in electricalimpedance brought about by differently sized particles or cells flowingthrough constriction 40 and impacting impedance of the electrical fieldacross or within constriction 40. In one implementation, sensor 38comprises an electrically charged high side electrode and a low sideelectrode formed within or integrated within a surface of channel 36within constriction 40. In one implementation, the low side electrode iselectrically grounded. In another implementation, the low side electrodeis a floating low side electrode. In other implementations, one ofsensors 438 or each of sensors 438 comprise other types of sensors fordetecting a characteristic or parameter of the sample fluid passingacross the associated constriction 40.

Temperature sensors 440 comprise sensors to output signals indicating atemperature of the sample fluid within chip 430. In one implementation,temperature sensors 440 are located to directly sense a temperature ofthe sample fluid within reservoir 34 or flowing through one or both ofpassages 336, 436. In yet another implementation, temperature sensors440 detector sense temperatures which correlate to the actualtemperature of the sample fluid contained within chip 430. In oneimplementation, each of temperature sensors 440 comprises an electricalresistance temperature sensor, wherein the resistance of the sensorvaries in response to changes in temperature such that signalsindicating the current electoral resistance of the sensor also indicateor correspond to a current temperature of the adjacent environment. Inother implementations, sensors 440 comprise other types of temperaturesensing devices.

Multiplexer circuitry 444 is formed in or upon substrate 32 andelectrically connects each of sensors 338, 438, pumps 360, 460 andtemperature sensors 440 to electrical connectors 152. Multiplexercircuitry 444 facilitates control and/or communication with a number ofsensors, pumps and temperature sensors that is greater than the numberof individual electrical connectors on chip 430. For example, despitechip 430 having a number n of contact pads, communication is availablewith a number of different independent components having a numbergreater than n. As a result, valuable space or real estate is conserved,facilitating a reduction in size of chip 430 and the testing device inwhich chip 430 is utilized.

Although chip 430 is illustrated as comprising each of sensors 338, 438,pumps 360, 460 and temperature sensors 440, in other implementations,not all of such components are provided on chip 430. In suchimplementations, multiplexer circuitry 444 is still employed to achievespace conservation with respect to chip 430. In particular, multiplexercircuitry 444 facilitates communication with a number of sensors 338,438 utilizing a number of electric contacts 152 connected to and forsensors 338, 438 which are fewer in number. Multiplexer circuitry 444facilitates communication with a number of pumps 360, 460 utilizing anumber of electric contacts 152 connected to and for temperature sensors440 which are fewer in number, with a number of sensors 338, 438utilizing a number of electric contacts 152 connected to and fortemperature sensors 440 which are fewer in number.

Portable electronic device 432 comprises a mobile electronic device toreceive data from microfluidic chip 430. Portable electronic device 432is releasably or removably connected to chip 430, either directly orindirectly via electrical are connected to additional electricalconnectors. In one implementation, portable electronic device 432communicate with chip 430 indirectly across additional electricalconnectors associated with a microfluidic cassette carrying chip 430,wherein the additional electrical connectors are themselves connected toelectrical connectors 152. Portable electronic device 432 forms variesfunctions using data received from chip 430. For example, in oneimplementation, portable electronic device 432 stores the data. Inanother implementation, portable electronic device 432 additionally oralternatively manipulates a processes the data. In yet anotherimplementation, portable electronic device 432 additionally oralternatively displays the data and/or further transmits the data acrossa local area network or wide area network to a server providingadditional storage and/or processing capabilities.

In the example illustrated, portable electronic device 432 comprisesdisplay 470, processor 472, memory 474, electrical connectors 476 andmultiplexer circuitry 478. Display 470 comprises a monitor or screen bywhich data is visually presented. In one implementation, display 470facilitates a presentation of graphical plots based upon data receivedfrom chip 430. In some implementations, display 470 may be omitted ormay be replaced with other data communication elements such as lightemitting diodes, auditory devices are or other elements that indicateresults based upon signals or data received from chip 430.

Processor 472 comprises at least one processing unit to generate controlsignals controlling the operation of sensors 338, 438, pumps 360, 460and temperature sensors 440 as well as the acquisition of data fromsensors 338, 438 and sensors 440. In the example illustrated, processor472 further analyzes data received from chip 430 to generate output thatis stored in memory 474, displayed on display 470 as lessor furthertransmitted across a network. For purposes of this application, the term“processing unit” shall mean a presently developed or future developedprocessing unit that executes sequences of instructions contained inmemory 474. Memory 474 comprises a non-transitory computer-readablemedium containing program logic to direct the operation of theprocessing unit. Execution of the sequences of instructions causes theprocessing unit to perform actions such as generating control signals.The instructions may be loaded in a random access memory (RAM) forexecution by the processing unit from a read only memory (ROM), a massstorage device, or some other persistent storage. In other examples,hard wired circuitry may be used in place of or in combination withmachine readable instructions to implement the functions described. Forexample, processor 472 and memory 474 may be embodied as part of anapplication-specific integrated circuit (ASIC). Unless otherwisespecifically noted, the controller is not limited to any specificcombination of hardware circuitry and machine readable instructions, norto any particular source for the instructions executed by the processingunit.

Electrical connectors 476 comprises devices by which portable electronicdevice 432 is releasably electrically connected directly or indirectlyto electrical connectors 152 of microfluidic chip 430. In oneimplementation, the electric connection provided by electrical connector476 facilitates transmission of electrical power for powering componentsof microfluidic chip 430. In one implementation, the electric connectionprovided by electrical connectors 476 facilitates transmission ofelectrical power in the form of electrical signals providing datatransmission to microfluidic chip 430 to facilitate control ofcomponents of microfluidic chip 430. In one implementation, electricconnection provided by electrical connector 476 facilitates transmissionof electrical power in the form electrical signals to facilitate thetransmission of data from microfluidic chip 430 to the portableelectronic device 432, such as the transmission of signals from sensorsensors 338, 438 and/or sensors 440. In one implementation, electricalconnector 476 facilitates each of the powering of microfluidic chip 430as well as the transmission of data signals to and from microfluidicchip 430.

In the example illustrated, electrical connectors 476 comprise aplurality of electrical contact pads which make contact withcorresponding pads of either (A) microfluidic chip 430, (B) of acassette wherein such pads are electrically connected to electricalconnectors 152 or (C) an intermediate connection interface or device. Inyet another implementation, electrical connectors 476 comprise aplurality of electrical prongs or pins, a plurality of electrical pin orprong receptacles, or a combination of both.

Electrical connectors 476 facilitates releasable electrical connectionof portable electronic device 432 to chip 430 such that portableelectronic device 432 may be separated from the chip 430, facilitatinguse of portable electronic device 432 with multiple interchangeablechips 430 (or their cassettes) as well as disposal or storage of themicrofluidic cassette 110 with the analyzed fluid, such as blood,contained within discharge reservoir 156. Electrical connectors 476provide modularization, allowing the portable electronic device 432 andassociated fluid analytical circuitry to be repeatedly reused while thechip 430 and its cassette 110 are separated for storage or disposal.

Multiplexer circuitry 478 is formed within portable electronic device432 and electrically connects processor 472 to electrical connectors476. Multiplexer circuitry 478 cooperates with multiplexer circuitry 444on chip 430 to control and/or facilitate communication with a number ofsensors, pumps and temperature sensors that is greater than the numberof individual electrical connectors 152 and 476. For example, despitechip 430 and portable electronic device 432 having a number n of contactpads, communication is available with a number of different independentcomponents having a number greater than n. As a result, valuable spaceor real estate on the chip is conserved, facilitating a reduction insize of chip 430 and the testing device in which chip 430 is utilized.

In one implementation, portable electronic device 432 comprises a tabletcomputer. In other implementations, portable electronic device 432comprises a smart phone or laptop or notebook computer. In yet otherimplementations, portable electronic device 432 is replaced with astationary computing device, such as a desktop computer or all-in-onecomputer.

FIG. 6 schematically illustrates an example microfluidic channel 536 andexample relative spacings of sensors 538A, 538B (collectively referredto as sensors 538) and of pump 560. In the example illustrated, sensors538 are similar to one another and comprise microfabricated integratedelectrical impedance sensors that detect characteristics of cells orparticles of fluid flowing across such sensors based upon changes inelectrical impedance. Pump 560 comprises a thermal resistor that heatsadjacent fluid to a temperature above a new creation energy of the fluidthus accretive a verb bubble to pump fluid along channel 536.

As shown by FIG. 6, sensor 538A is positioned within a firstconstriction 40 has a length L1 along channel 536. Sensor 538B ispositioned within channel 536 within a second constriction 40 and isspaced from sensor 538A by distance D1. Distance D1 is at least twicelength L1. As a result, crosstalk between such sensors 538 is reduced.

In one implementation, sensors 538 each have a length L1 of at least 4μm less than equal to 10 μm, Each of such sensors 538 has a width W thatis greater than or equal to half of the width of the constriction 40 inwhich the sensors located. In some implementations, constriction 40 isomitted, wherein sensors 538 are located within a portion of channel 536having an unchanging cross-sectional area. In one implementation, thecross-sectional dimension of the portion of channel 536 in which suchsensors are located is at least 5 μm in diameter and less than or equalto 40 μm in diameter.

As further shown by FIG. 6, pump 560 is positioned within channel 536and has a length L2 along channel 536. Pump 560 and the next adjacentsensor, sensor 538A, are spaced apart from one another within channel536 by a distance D2. Distance D2 is greater than or equal to the lengthL2 of pump 560. Pump 560 is spaced from the mouth 541 of channel 536 tomicrofluidic reservoir 34 by a distance D3. Distance D3 is also greaterthan or equal to the length L2 of pump 560. Such spacings facilitatesteady flow of particles or cells of the fluid over sensors 538.

FIG. 7 illustrates an example microfluidic diagnostic or testing system1000. System 1000 comprises a portable electronic device driven,impedance-based system by which samples of fluid, such as blood samples,are analyzed. For purposes of this disclosure, the term “fluid”comprises the analyte in or carried by the fluid such as a cell,particle or other biological substance. The impedance of the fluidrefers to the impedance of the fluid and/or any analyte in the fluid.System 1000, portions of which are schematically illustrated, comprisesmicrofluidic cassette 1010, cassette interface 1200, mobile analyzer1232 and remote analyzer 1300. Overall, microfluidic cassette 1010receives a fluid sample and outputs signals based upon sensedcharacteristics of the fluid sample. Interface 1200 serves as anintermediary between mobile analyzer 1232 and cassette 1010. Interface1200 removably connects to cassette 1010 and facilitates transmission ofelectrical power from mobile analyzer 1232 to cassette 1010 to operatepumps and sensors on cassette 1010. Interface 1200 further facilitatescontrol of the pumps and sensors on cassette 1010 by mobile analyzer1232. Mobile analyzer 1232 controls the operation cassette 1010 throughinterface 1200 and receive data produced by cassette 1010 pertaining tothe fluid sample being tested. Mobile analyzer 1232 analyzes data andproduces output. Mobile analyzer 1232 further transmits processed datato remote analyzer 1300 for further more detailed analysis andprocessing. System 1000 provides a portable diagnostic platform fortesting fluid samples, such as blood samples.

FIGS. 8-21 illustrate microfluidic cassette 1010 in detail. As shown byFIGS. 8-10, cassette 1010 comprises cassette board 1012, cassette body1014, membrane 1015 and microfluidic chip 1030. Cassette board 1012,shown in FIGS. 10A and 10B, comprises a panel or platform in which orupon which fluid chip 1030 is mounted. Cassette board 1012 compriseselectrically conductive lines or traces 1015 which extend fromelectrical connectors of the microfluidic chip 1030 to electricalconnectors 1016 on an end portion of cassette board 1012. As shown inFIG. 8, electrical connectors 1016 are exposed on an exterior cassettebody 1014. As shown by FIG. 7, the exposed electrical connectors 1016 tobe inserted into interface 1200 so as to be positioned in electricalcontact with corresponding electrical connectors within interface 1200,providing electrical connection between microfluidic chip 1030 andcassette interface 1200.

Cassette body 1014 partially surrounds cassette board 1012 so as tocover and protect cassette board 1012 and microfluidic chip 1030.Cassette body 1014 facilitates manual manipulation of cassette 1010,facilitating manual positioning of cassette 1010 into releasableinterconnection with interface 1200. Cassette body 1014 additionallypositions and seals against a person's finger during the acquisition ofa fluid or blood sample while directing the received fluid sample tomicrofluidic chip 1030.

In the example illustrated, cassette body 1014 comprises finger gripportion 1017, sample receiving port 1018, residence passage 1020, sampleholding chamber 1021, chip funnel 1022, vent 1023 and dischargereservoir 1024. Finger grip portion 1017 comprises a thin portion ofbody 1014 opposite to the end of cassette 1010 at which electricalconnectors 1016 are located. Finger grip portion 1017 facilitatesgripping of cassette 1010 in connection or insertion of cassette 1010into a receiving port 1204 of cassette interface 1200 (shown in FIG. 7).In the example illustrated, finger grip portion 1017 has a width W ofless than or equal to 2 inches, a length L of less than or equal to 2inches and a thickness of less than or equal to 0.5 inches.

Sample receiving port 1018 comprises an opening into which a fluidsample, such as a blood sample, is to be received. In the exampleillustrated, sample receiving port 1018 has a mouth 1031 that is formedon a top surface 1027 of an elevated platform or mound 1026 that extendsbetween finger grip portion 1017 and the exposed portion of cassettehoard 1012. Mound 1026 clearly identifies the location of samplereceiving port 1018 for the intuitive use of cassette 1010. In oneimplementation, the top surface 1027 is curved or concave to match orapproximately match the lower concave surface of a finger of a person soas to form an enhanced seal against the bottom of the person's fingerfrom which the sample is taken. Capillary action pulls in blood from thefinger which forms the sample. In one implementation, the blood sampleis of 5 to 10 microliters. In other implementations, port 1018 islocated at alternative locations or mound 1026 is omitted, for example,as depicted in FIG. 9A. Although FIG. 9A illustrates cassette 1010having a slightly different outer configuration for cassette body 1014as compared to body 1014 shown in FIG. 8, wherein the cassette body 1014shown in FIG. 9A omits mound 1026, those remaining elements orcomponents shown in FIGS. 8 and 9A are found in both of the cassettebodies shown in FIGS. 8 and 9A.

As shown by FIGS. 9A-9C, residence passage 1020 comprises a fluidchannel, conduit, tube or other passage extending between sample inputport 1018 and sample holding chamber 102L Residence passage 1020 extendsbetween sample input port 1018 and sample holding chamber 1021 in atortuous fashion, an indirect or non-linear fashion full of twists andturns, to lengthen the time for a received sample, input through sampleinput port 1018, to travel or flow to chip 1030. Residence passage 1018provides a volume in which the fluid sample being tested and a fluidreagent may mix prior to reaching chip 1030. In the example illustrated,residence passage 263 is circuitous, comprising a circular or helicalpassage winding in the space of cassette body 1012 between port 1018 andchip 1030. In another implementation, residence passage 1020 twists andturns, zigzags, snakes, serpentines and/or meanders in a zigzag fashionwithin the space between sample input port 1018 and chip 1030.

In the example illustrated, residence passage 1020 extends in a downwarddirection towards microfluidic chip 1030 (in the direction of gravity)and subsequently extends in an upward direction away from microfluidicchip 1030 (in a direction opposite to that of gravity). For example, asshown by FIGS. 9A and 9B, upstream portions 1028 extend vertically belowthe downstream end portion 1029 of residence passage 1020 that isadjacent to and directly connected to sample holding chamber 1021.Although upstream portions receive fluid from input port 1018 before endportion 1029, end portion 1029 is physically closer to input port 1018in a vertical direction. As a result, fluid flowing from the upstreamportions flows against gravity to the downstream or end portion 1029. Asdescribed hereafter, in some implementations, residence passage 1020contains a reagent 1025 which reacts with the fluid sample or bloodsample being tested. In some circumstances, this reaction will produceresidue or fallout. For example, a fluid sample such as blood that hasundergone lysis will have lysed cells or lysate. Because end portion1029 of residence passage 1020 extends above upstream portions 1028 ofresidence passage 1020, such residue or fallout resulting from thereaction of the fluid sample with reagent 1025 settles out and istrapped or retained within such upstream portions 1028. In other words,the amount of such residue or fallout passing through residence passage1020 to microfluidic chip 1030 is reduced. In other implementations,residence passage 1020 extends in a downward direction to sample holdingchamber 1021 throughout its entire course.

Sample holding chamber 1021 comprises a chamber or internal volume inwhich the fluid sample or blood sample being tested collects above chip1030. Chip funnel 1022 comprises a funneling device that narrows down tochip 1030 so as to funnel the larger area of chamber 1021 to the smallerfluid receiving area of chip 1030. In the example illustrated, sampleinput port 1018, residence passage 1020, sample holding chamber 1021 andchip funnel 1022 form an internal fluid preparation zone in which afluid or blood sample may be mixed with a reagent before entering chip1030. In one implementation, the fluid preparation zone has a totalvolume of 20 to 250 μL. In other implementations, the fluid preparationzone provided by such internal cavities may have other volumes.

As indicated by stippling in FIG. 9A, in one implementation, cassette1010 is prefilled with a fluid reagent 1025 prior to insertion of asample fluid to be tested into port 1018. Fluid reagent 1025 comprises acomposition that interacts with the fluid to be tested, enhancing theability of microfluidic chip 130 to analyze a selected characteristic ora group of selected characteristics of the fluid to be tested. In oneimplementation, fluid reagent 1025 comprises a composition to dilute thefluid being tested. In one implementation, fluid reagent 1025 comprisesa composition to perform lysis on the fluid or blood being tested. Inyet another implementation, fluid reagent 264 comprises a composition tofacilitate tagging of selected portions of the fluid being tested. Forexample, in one implementation, fluid reagent 1025 comprises magneticbeads, gold beads or latex beads. In other implementations, fluidreagent 1025 comprises other liquid or solid compositions or liquids,distinct from the sample fluid to be tested, that interact with or thatmodify the sample fluid placed within sample input port 1018 prior tothe sample fluid being received, processed and analyzed by microfluidicchip 1030.

Vents 1023 comprise passages communicating between sample holdingchamber 1021 and the exterior of cassette body 1014. In the exampleillustrated in FIG. 8, vents 1023 extend through the side of mount 1026.Vents 1023 are sized small enough to retain fluid within sample holdingchamber 1021 through capillary action but large enough so as to permitair within holding chamber 1021 to escape as holding chamber 1021 isfilled with fluid. In one implementation, each of their vents has anopening or diameter of 50 to 200 micrometers.

Discharge reservoir 1024 comprises a cavity or chamber within body 1014arranged to receive fluid discharged from chip 1030. Discharge reservoir1024 is to contain fluid that has been passed through chip 1030 and thathas been processed or tested. Discharge reservoir 1024 receivesprocessed or tested fluid such that the same fluid is not testedmultiple times. In the example illustrated, discharge reservoir 1024 isformed in body 1014 below chip 1030 or on a side of chip 1030 oppositeto that of chip funnel 1022 and sample holding chamber 1021 such thatchip 1030 is sandwiched between chip funnel 1022 and discharge reservoir1024. In one implementation, discharge reservoir 1024 is completelycontained within body 1014 and is inaccessible (but through thedestruction of body 1014 such as by cutting, drilling or other permanentdestruction or breaking of body 1014), locking the processed or testedfluid within body 112 for storage or subsequent sanitary disposal alongwith disposal of cassette 1010. In yet another implementation, dischargereservoir 1024 is accessible through a door or septum, allowingprocessed or tested fluid to be withdrawn from reservoir 1020 forfurther analysis of the tested fluid, for storage of the tested fluid ina separate container or for emptying of reservoir 1024 to facilitatecontinued use of cassette 1010.

In some implementations, microfluidic reservoir 1024 is omitted. In suchimplementations, those portions of the fluid samples or blood samplesthat have been tested are processed by microfluidic chip 1030 arerecirculated back to an input side or input portion of microfluidic chip1030. For example, in one implementation, microfluidic chip 1030comprises a microfluidic reservoir which receives fluid through chipfunnel 1022 on a input side of the sensor or sensors provided bymicrofluidic chip 1030. Those portions of a fluid sample or blood samplethat have been tested are returned back to the microfluidic reservoir onthe input side of the sensor or sensors of microfluidic chip 1030.

Membrane 1015 comprises an imperforate, liquid impermeable panel, filmor other layer of material adhesively are otherwise secured in place soas to extend completely across and completely cover mouth 1031 of port1018. In one implementation, membrane 1015 serves as a tamper indicatoridentifying if the interior volume of cassette 1010 and its intendedcontents have been compromised or tampered with. In implementationswhere the sample preparation zone of cassette 1010 has been prefilledwith a reagent, such as reagent 1025 described above, membrane 1015seals the fluid reagent 1025 within the fluid preparation zone, withinport 1018, residence passage 1020, fluid holding chamber 1021 and chipfunnel 1022. In some implementations, membrane 1015 additionally extendsacross vents 1023. Some implementations, membrane 1015 is additionallygas or air impermeable.

In the example illustrated, membrane 1015 seals or contains fluidreagent 1025 within cassette 1010 at least until the fluid sample is tobe deposited into sample input port 1018. At such time, membrane 1015may be peeled away, torn or punctured to permit insertion of the fluidsample through mouth 1018. In other implementations, membrane 1015 maycomprises septum through which a needle is inserted to deposit a fluidor blood sample through mouth 1018. Membrane 1015 facilitatespre-packaging of fluid reagent 1025 as part of cassette 1010, whereinthe fluid agent 1025 is ready for use with the subsequent deposits ofthe fluid sample to be tested. For example, a first cassette 1010containing a first fluid reagent 1025 may be predesigned for testing afirst characteristic of a first sample of fluid while a second cassette1010 containing a second fluid reagent 1025, different than the firstfluid reagent 1025, may be predesigned for testing a secondcharacteristic of a second sample of fluid. In other words, differentcassettes 1010 may be specifically designed for testing differentcharacteristics depending upon the type or a quantity of fluid reagent1025 contained therein.

FIGS. 10A, 10B and 11 illustrate microfluidic chip 1030. FIG. 10Aillustrates a top side of cassette board 1012, chip funnel 1022 andmicrofluidic chip 1030. FIG. 10A illustrates microfluidic chip 1030sandwiched between chip funnel 1022 and cassette board 1012. FIG. 10Billustrate a bottom side of the set board 1012 and microfluidic chip1030. FIG. 11 is a cross-sectional view of microfluidic chip 1030 belowchip funnel 1022. As shown by FIG. 11, microfluidic chip 1030 comprisesa substrate 1032 formed from a material such as silicon. Microfluidicchip 1030 comprises a microfluidic reservoir 1034 formed in substrate1032 and which extends below chip funnel 1022 to receive the fluidsample (with a reagent in some tests) into chip 1030. In the exampleillustrated, microfluidic reservoir has a mouth or top opening having awidth W of less than 1 mm and nominally 0.5 mm. Reservoir 1030 has adepth D of between 0.5 mm and 1 mm and nominally 0.7 mm. As will bedescribed hereafter, microfluidic chip 1030 comprises pumps and sensorsalong a bottom portion of chip 1030 in region 1033.

FIGS. 12 and 13 are enlarged views of microfluidic chip 1130, an exampleimplementation of microfluidic chip 1030. Microfluidic chip 1130integrates each of the functions of fluid pumping, impedance sensing andtemperature sensing on a low-power platform. Microfluidic chip 1130 isspecifically for use with a cassette 1010 having a cassette body 1014that omits discharge reservoir 1024. As will be described hereafter,microfluidic chip 1133 recirculates portions of a fluid sample, that hasbeen tested, back to an input or upstream side of the sensors ofmicrofluidic chip 1133. As shown by FIG. 12, microfluidic chip 1030comprises substrate 1032 in which is formed microfluidic reservoir 1034(described above). In addition, microfluidic chip 1130 comprisesmultiple sensing regions 735, each sensing region comprising amicrofluidic channel 1136, micro-fabricated integrated sensors 1138, anda pump 1160.

FIG. 13 is an enlarged view illustrating one of sensing regions 1135 ofchip 1130 shown in FIG. 12. As shown by FIG. 13, microfluidic channel.1136 comprises a passage extending within or formed within substrate1032 for the flow of a fluid sample. Channel 1136 comprises a pumpcontaining central portion 1162 and a pair of sensor containing branchportions 1164, 1166. Each of branch portions 1164, 1166 comprises afunnel-shaped mouth that widens towards microfluidic reservoir 1134.Central portion 1162 extends from microfluidic reservoir 1134 with anarrower mouth opening to microfluidic reservoir 1134. Central portion1162 contains pump 1160.

Sensor containing branch portions 1164, 1166 stem or branch off ofopposite sides of central portion 162 and extend back to microfluidicreservoir 1134. Each of branch portions 1164, 1166 comprises a narrowingportion, throat or constriction 1140 through with the fluid flows.

In one implementation, branch portions 1164, 1166 are similar to oneanother. In another implementation, branch portions 1164, 1166 areshaped or dimensioned different from one another so as to facilitatedifferent fluid flow characteristics. For example, the constrictions1140 or other regions of portions 1164, 1166 may be differently sizedsuch that particles or cells of a first size more readily flow through,if at all, through one of portions 364, 366 as compared to the other ofportions 1164, 1166. Because portions 1164, 1166 diverge from oppositesides of central portion 1162, both of portions 1164, 1166 receive fluiddirectly from portion 1162 without fluid being siphoned to any otherportions beforehand.

Each of micro-fabricated integrated sensors 1138 comprises amicro-fabricated device formed upon substrate 1032 within constriction1140. In one implementation, sensor 1138 comprises a micro-device thatis designed to output electrical signals or cause changes in electricalsignals that indicate properties, parameters or characteristics of thefluid and/or cells/particles of the fluid passing through constriction1140. In one implementation, each of sensors 1138 comprises acell/particle sensor that detects properties of cells or particlescontained in a fluid and/or that detects the number of cells orparticles in fluid passing across sensor 1138. For example, in oneimplementation, sensor 1138 comprises an electric sensor which outputssignals based upon changes in electrical impedance brought about bydifferently sized particles or cells flowing through constriction 1140and impacting impedance of the electrical field across or withinconstriction 1140. In one implementation, sensor 1138 comprises anelectrically charged high side electrode and a low side electrode formedwithin or integrated within a surface of channel 1136 withinconstriction 40. In one implementation, the low side electrode iselectrically grounded. In another implementation, low side electrodecomprises a floating low side electrode. For purposes of thisdisclosure, a “floating” low side electrode refers to an electrodehaving all connecting admittances zero. In other words, the floatingelectrode is disconnected, not being connected to another circuit or toearth.

FIGS. 14-16 illustrate one example of sensor 1138. As shown by FIG. 14,in one implementation, sensor 1138 comprises an electric sensorcomprising low side electrodes 1141, 1143 and charged or active highside electrode 1145. Low side electrodes are either grounded or arefloating. Active electrode 1145 is sandwiched between groundingelectrodes 143. Electrodes 1141, 1143 and 1145, forming electric sensor1138, are located within a constriction 1140 formed within channel 1136.Constriction 1140 comprises a region of channel 1136 that has a smallercross-sectional area than both adjacent regions of channel 36, upstreamand downstream of constriction 1140.

FIG. 15 illustrates one example sizing or dimensioning of constriction1140. Constriction 1140 has a cross-sectional area similar to that ofthe individual particles or cells that pass through constriction 1140and which are being tested. In one implementation in which the cells1147 being tested have a general or average maximum dimension of 6 μm,constriction 1140 has a cross-sectional area of 100 μm². In oneimplementation, constriction 1140 has a sensing volume of 1000 μm³. Forexample, in one implementation, constriction 1140 has a sense volumeforming a region having a length of 10 μm, a width of 10 μm and a heightof 10 μm. In one implementation, constriction 1140 has a width of nogreater than 30 μm. The sizing or dimensioning of constriction 1140restricts the number of particles or individual cells that may passthrough constriction 1140 at any one moment, facilitating testing ofindividual cells or particles passing through constriction 1140.

FIG. 16 illustrates the forming an electric field by the electrodes ofelectric sensor 1138. As shown by FIG. 16, low side electrodes 1143share active or high side electrode 1145, wherein an electrical field isformed between active high side electrode 1145 and each of the two lowside electrodes 1141, 1143. In one implementation, low side electrodes1141, 1143 are likely grounded. In another implementation, low sideelectrode 1141, 1143 comprise floating low side electrodes. As fluidflows across the electrodes 1141, 1143, 1145 and through the electricalfield, the particles, cells or other analyte within the fluid impact theimpedance of the electrical field. This impedance is sensed to identifycharacteristics of the cells or particles or to count the number ofcells or particles passing through the electric field.

Pump 1160 comprises a device to move fluid through microfluidic channel1136 and through constrictions 1140 across one of sensors 1138. Pump1160 draws fluid from microfluidic reservoir 1134 into channel 1136.Pump 1160 further circulates fluid that has passed through constriction1140 and across sensor 1138 back to microfluidic reservoir 1134.

In the example illustrated, pump 1160 comprises a resistor actuatable toeither of a pumping state or a temperature regulating state. Resistor isformed from electrically resistive materials that are capable ofemitting a sufficient amount of heat so as to heat adjacent fluid to atemperature above a nucleation energy of the fluid. Resistor is furthercapable of emitting tower quantities of heat so as to heat fluidadjacent resistor to a temperature below a nucleation energy of thefluid such that the fluid is heated to a higher temperature withoutbeing vaporized.

When the resistor forming pump 1160 is in the pumping state, pulses ofelectrical current passing through the resistor cause resistor toproduce heat, heating adjacent fluid to a temperature above a nucleationenergy of the adjacent fluid to create a vapor bubble which forcefullyexpels fluid across constrictions 1140 and back into reservoir 1134.Upon collapse of the bubble, negative pressure draws fluid frommicrofluidic reservoir 1134 into channel 1136 to occupy the prior volumeof the collapsed bubble.

When the resistor forming pump 1160 is in the temperature regulatingstate or fluid heating state, the temperature of adjacent fluid rises toa first temperature below a nucleation energy of the fluid and thenmaintains or adjusts the operational state such that the temperature ofthe adjacent fluid is maintained constant or constantly within apredefined range of temperatures that is below the nucleation energy. Incontrast, when resistor is being actuated to a pumping state, resistoris in an operational state such that the temperature of fluid adjacentthe resistor is not maintained at a constant temperature or constantlywithin a predefined range of temperatures (both rising and fallingwithin the predefined range of temperatures), but rapidly andcontinuously increases or ramps up to a temperature above the nucleationenergy of the fluid.

In yet other implementations, pump 1160 may comprise other pumpingdevices. For example, in other implementations, pump 1160 may comprise apiezo-resistive device that changes shape or vibrates in response toapplied electrical current to move a diaphragm to thereby move adjacentfluid across constrictions 1140 and hack to microfluidic reservoir 1134.In yet other implementations, pump 1160 may comprise other microfluidicpumping devices in fluid communication with microfluidic channel 1136.

As indicated by arrows in FIG. 13, actuation of pump 1160 to the fluidpumping state moves the fluid sample through central portion 1162 in thedirection indicated by arrow 1170. The fluid sample flows throughconstrictions 1140 and across sensors 1138, where the cells within thefluid sample impact the electric field (shown in FIG. 16) and whereinthe impedance is measured or detected to identify a characteristic ofsuch cells or particles and/or to count the number of cells flowingacross the sensing volume of sensor 1138 during a particular interval oftime. After passing through constrictions 1140, portions of the fluidsample continue to flow back to microfluidic reservoir 1134 as indicatedby arrows 1171.

As further shown by FIG. 12, microfluidic chip 1130 additionallycomprises temperature sensors 1175, electrical contact pads 1177 andmultiplex or circuitry 1179. Temperature sensors 1175 are located atvarious locations amongst the sensing regions 1135. Each of temperaturesensors 1175 comprises a temperature sensing device to directly orindirectly output signals indicative of a temperature of portions of thefluid sample in the microfluidic channel 1136. In the exampleillustrated, each of temperature sensors 1135 is located external tochannel 36 to indirectly sense a temperature of the sample fluid withinchannel 1136. In other implementations, temperature sensors 1175 arelocated within microfluidic reservoir 1134 to directly sense atemperature of the sample fluid within microfluidic reservoir 1134. Inyet another implementation, temperature sensors 1175 are located withinchannel 1136. In yet other implementations, temperature sensor 1135 maybe located at other locations, wherein the temperature at such otherlocations is correlated to the temperature of the sample fluid beingtested. In one implementation, temperature sensors 1135 output signalswhich are aggregated and statistically analyzed as a group to identifystatistical value for the temperature of the sample fluid being tested,such as an average temperature of the sample fluid being tested. In oneimplementation, chip 1130 comprises multiple temperature sensors 1175within microfluidic reservoir 1134, multiple temperature sensors 1175within channel 1136 and/or multiple temperature sensors external to thefluid receiving volume provided by microfluidic reservoir 1134 andchannel 1136, within the substrate of chip 1130.

In one implementation, each of temperature sensors 1175 comprises anelectrical resistance temperature sensor, wherein the resistance of thesensor varies in response to changes in temperature such that signalsindicating the current electrical resistance of the sensor also indicateor correspond to a current temperature of the adjacent environment. Inother implementations, temperature sensors 1175 comprise other types ofmicro-fabricated or microscopic temperature sensing devices.

Electrical contact pads 1177 are located on end portions of microfluidicchip 1130 which are spaced from one another by less than 3 mm andnominally less than 2 mm, providing microfluidic chip 1130 with acompact length facilitates the compact size of cassette 1010. Electricalcontact pads 1177 sandwich the microfluidic and sensing regions 1135 andare electrically connected to sensors 1138, pumps 1160 and temperaturesensors 1175. Electrical contact pads 1177 are further electricallyconnected to the electrical connectors 1016 of cassette board 1012(shown in FIGS. 9B, 9C 10A and 10B.

Multiplexer circuitry 1179 is electrically coupled between electricalcontact pads 1177 and sensors 1138, pumps 1160 and temperature sensors1175. Multiplexer circuitry 1179 facilitates control and/orcommunication with a number of sensors 1138, pumps 1160 and temperaturesensors 1175 that is greater than the number of individual electricalcontact pads 1177 on chip 430. For example, despite chip 1130 having anumber n of contact pads, communication is available with a number ofdifferent independent components having a number greater than n. As aresult, valuable space or real estate is conserved, facilitating areduction in size of chip 1130 and cassette 1010 in which chip 1130 isutilized. In other implementations, multiplexer circuitry 1179 may beomitted.

FIG. 17 is an enlarged view of a portion of microfluidic chip 1230,another example implementation of microfluidic chip 1030. Similar tomicrofluidic chip 1130, microfluidic chip 1430 comprises temperaturesensors 1175, electrical contact pads 1177 and multiplexer circuitry1179 illustrated and described above with respect to microfluidic chip1130. Like microfluidic chip 1130, microfluidic chip 1230 comprisessensor regions comprising an electric sensor 1138 and a pump 1160.Microfluidic chip 1230 additionally comprises temperature sensors 1175dispersed throughout. Microfluidic chip 1230 is similar to microfluidicchip 1130 except that microfluidic chip 1230 comprises differently sizedor dimensioned microfluidic channels. In the example illustrated,microfluidic chip 1230 comprises U-shaped microfluidic channels 1236Aand 1236B (collectively referred to as microfluidic channels 1236).Microfluidic channels 1236A have a first width while microfluidicchannels 1236B have a second with less than the first width.

Because microfluidic channels 1236 have different widths or differentcross-sectional areas, channels 1236 receive differently sized cells orparticles in the fluid sample for testing. In one such implementation,the different sensors 1138 in the differently sized channels 1236 areoperated at different frequencies of alternating current such performdifferent tests upon the differently sized cells in the differentlysized channels 1236. In another of such implementations, the differentlysized channels 1236 contain a different type or different electricsensor 1138 to detect different characteristics of the differently sizedcells, particles or other analyte passing through the differently sizedchannels 1236.

FIGS. 18 and 19 are enlarged views illustrating a portion ofmicrofluidic chip 1330, another example implementation of microfluidicchip 1030. Similar to microfluidic chip 1130, microfluidic chip 1430comprises temperature sensors 1175, electrical contact pads 1177 andmultiplexer circuitry 1179 illustrated and described above with respectto microfluidic chip 1130. Microfluidic chip 1330 is similar tomicrofluidic chip 1230 in that microfluidic chip 1330 comprisesmicrofluidic channel portions 1336A, 1336B and 1336C (collectivelyreferred to as channels 1336) of varying widths. Microfluidic chip 1330has a different geometry as compared to microfluidic chip 1230. As withmicrofluidic chip 1230, microfluidic chip 1330 comprises various sensingregions with the sensing region including an electric sensor 1138 and apump 1160.

FIG. 18 omits sensors 1138 and pumps 1160 to better illustrate channels1336. As shown by FIG. 18, channel portion 1336A has a width greaterthan the width of channel portion 1336B. Channel portion 1336B has awidth greater than the width of channel portion 1336C. Channel portion1336A extends from microfluidic reservoir 1134. Channel portion 1336Bextends from channel portion 1336A and continues back to microfluidicreservoir 1134. Channel portion 1336C branches off of channel portion1336B and returns to channel portion 1336B, as shown by FIG. 19, pump1160 is located within channel portion 1336A. Sensors 1138 are locatedwithin channel portion 1336B and channel portion 1336C. As a result, asingle pump 1160 pumps a fluid sample through both of channel portions1336B and 1336C across the respective sensors 1138 contained within thedifferently sized channels. Cells in all of the pumped fluid pass acrossand are sensed by sensor 1138 in channel portion 1336B. Those cells thatare sufficiently small to pass through the narrower channel portion1336C pass through and are sensed by the sensor 1138 in channel portion1336C. As a result, the sensor 1138 and channel portion 1336C senses asubset or less than complete portion of the cells and fluid pumped bypump 1160.

FIG. 20 is an enlarged view of a portion of microfluidic chip 1430,another example implementation of microfluidic chip 1030. Microfluidicchip 1430 is specifically designed for use with a cassette, such ascassette 1010, that comprises a discharge reservoir, such as dischargereservoir 1024 shown in FIG. 9A. Similar to microfluidic chip 1130,microfluidic chip 1430 comprises temperature sensors 1175, electricalcontact pads 1177 and multiplexer circuitry 1179 illustrated anddescribed above with respect to microfluidic chip 1130.

FIG. 20 illustrates one example sensing region 1435 of microfluidic chip1430, wherein microfluidic chip 1430 comprises multiple such sensingregions 1435. Microfluidic sensing region 1435 comprises microfluidicchannel 1436, fluid sensors 1138, pumps 1460 and discharge passages1462. Microfluidic channel 1436 is formed in substrate 1032 andcomprises inlet portion 1466 and branch portions 1468. Inlet portion1466 has a funnel shaped mouth extending from microfluidic reservoir1134. Inlet portion 466 facilitates inflow of fluid, including cells orparticles, into channel 1436 and through each of branch portions 1468.

Branch portions 1468 extend from opposite sides of central portion 1466.Each of branch portions 1468 terminate at an associated dischargepassage 1462. In the example illustrated, each of branch portions 1468comprises a constriction 1140 in which the sensor 1138 is located.

Pumps 1460 are located proximate to and nominally opposite to dischargepassages 1462 so as to pump fluid through discharge passages 1462 to theunderlying discharge reservoir 1024 (shown in FIG. 9A). Pumps 1460comprise resistors similar to pumps 1160 described above. In the pumpingstate, pumps 1460 receive electrical current the heat adjacent fluid toa temperature above a nucleation energy of the fluid so as to create avapor bubble which pushes fluid between pump 1460 and discharge passage1462 through discharge passage 1462 into the discharge reservoir 1024.Collapse of the vapor bubble draws portions of a fluid sample frommicrofluidic reservoir 1134, through central portion 1466 and acrosssensors 1138 in branch portions 1468.

Discharge passages 1462 extend from a portion of passage 1436 adjacentto pump 460 to discharge reservoir 156. Discharge passages 1462 inhibitreverse or backflow of fluid within discharge reservoir 1024 throughdischarge passages 1462 back into channel 1436. In one implementation,each of discharge passages 1462 comprises a nozzle through which fluidis pumped by pump 1460 into discharge reservoir 1024. In anotherimplementation, discharge passage 1462 comprises a unidirectional valve.

Referring hack to FIG. 7, cassette interface 1200 sometimes referred toas a “reader” or “dongle”, interconnects and serves as an interfacebetween cassette 1010 and mobile analyzer 1232. Cassette interface 1200contains components or circuitry that is dedicated, customized orspecifically to control components of microfluidic cassette 1010.Cassette interface 1200 facilitates use of a general portable electronicdevice, loaded with the appropriate machine readable instructions andapplication program interface, but wherein the portable electronicdevice may omit the hardware or firmware specifically used to enablecontrol of the components of cassette 1010. As a result, cassetteinterface 1200 facilitates use of multiple different portable electronicdevices 1232 which have simply been updated with an upload of anapplication program and an application programming interface. Cassetteinterface 1200 facilitates use of mobile analyzer 1232 that are notspecifically designated or customized for use just with the particularmicrofluidic cassette 1010. Said another way, cassette interface 1200facilitates use of mobile analyzer 1232 with multiple differentcassettes 1010 having different testing capabilities through theconnection of a different cassette interface 1200.

Cassette interface 1200 carries circuitry and electronic componentsdedicated or customized for the specific use of controlling theelectronic components of cassette 1010. Because cassette interface 1200carries much of the electronic circuitry and components specificallydedicated for controlling the electronic components of cassette 1010rather than such electronic components being carried by cassette 1010itself, cassette 1010 may be manufactured with fewer electroniccomponents, allowing the costs, complexity and size of cassette 1010 tobe reduced. As a result, cassette 1010 is more readily disposable afteruse due to its lower base cost. Likewise, because cassette interface1200 is releasably connected to cassette 210, cassette interface 1200 isreusable with multiple exchanged cassettes 1010. The electroniccomponents carried by cassette interface 1200 and dedicated orcustomized to the specific use of controlling the electronic componentsof a particular cassette 1010 are reusable with each of the differentcassettes 1010 when performing fluid or blood tests on different fluidsamples or fluid samples from different patients or sample donors.

In the example illustrated, cassette interface 1200 comprises electricalconnector 1204, electrical connector 1206 and firmware 1208(schematically illustrated external to the outer housing of interface1200), Electrical connector 1204 comprises a device by which cassetteinterface 1200 is releasably electrically connected directly toelectrical connectors 1016 of cassette 1010. In one implementation, theelectrical connection provided by electrical connector 1204 facilitatestransmission of electrical power for powering electronic components ofmicrofluidic chip 1030, 1130, 1230, 1330, 1430, such as electric sensors1138 or a microfluidic pump 1160. In one implementation, the electricalconnection provided by electrical connector 1204 facilitatestransmission of electrical power in the form of electrical signalsproviding data transmission to microfluidic chip 1030, 1130, 1230, 1330,1430 to facilitate control of components of microfluidic chip 1030,1130, 1230, 1330, 1430. In one implementation, the electrical connectionprovided by electrical connector 1204 facilitates transmission ofelectrical power in the form electrical signals to facilitate thetransmission of data from microfluidic chip 1030, 1130, 1230, 1330, 1430to the mobile analyzer 1232, such as the transmission of signals fromsensors 38. In one implementation, electrical connector 1204 facilitateseach of the powering of microfluidic chip 1030, 1130, 1230, 1330, 1430as well as the transmission of data signals to and from microfluidicchip 1030, 1130, 1230, 1330, 1430.

In the example illustrated, electrical connectors 1204 comprise aplurality of electrical contact pads located in a female port, whereinthe electrical contact pads which make contact with corresponding pads1016 of cassette 1010. In yet another implementation, electricalconnectors 1204 comprise a plurality of electrical prongs or pins, aplurality of electrical pin or prong receptacles, or a combination ofboth. In one implementation, electrical connector 1204 comprises auniversal serial bus (USB) connector port to receive one end of a USBconnector cord, wherein the other end of the USB connector cord isconnected to cassette 210. In still other implementations, electricalconnector 1204 may be omitted, where cassette interface 1200 comprises awireless communication device, such as infrared, RF, BLUETOOTH®, otherwireless technologies for wirelessly communicating between interface1200 and cassette 1010.

Electrical connector 1204 facilitates releasable electrical connectionof cassette interface 1200 to cassette 1010 such that cassette interface1200 may be separated from cassette 1010, facilitating use of cassetteinterface 1200 with multiple interchangeable cassettes 1010 as well asdisposal or storage of the microfluidic cassette 1010 with the analyzedfluid, such as blood. Electrical connectors 1204 facilitatemodularization, allowing cassette interface 1200 and associatedcircuitry to be repeatedly reused while cassette 1010 is separated forstorage or disposal.

Electrical connector 1206 facilitates releasable connection of cassetteinterface 1200 to mobile analyzer 1232. As a result, electricalconnector 1206 facilitates use of cassette interface 1200 with multipledifferent portable electronic devices 1232. In the example illustrated,electrical connector 1206 comprises a universal serial bus (USB)connector port to receive one end of a USB connector cord 1209, whereinthe other end of the USB connector cord 1209 is connected to the mobileanalyzer 1232. In other implementations, electrical connector 1206comprises a plurality of distinct electrical contact pads which makecontact with corresponding blood connectors of mobile analyzer 1232,such as where one of interface 1200 and mobile analyzer 1232 directlypine into the other of interface 1200 and mobile analyzer 1232. Inanother implementation, electrical connector 1206 comprises prongs orprong receiving receptacles. In still other implementations, electricalconnector 1206 may be omitted, where cassette interface 1200 comprises awireless communication device, utilizing infrared, RF, BLUETOOTH®, orother wireless technologies for wirelessly communicating betweeninterface 1200 and mobile analyzer 1232.

Firmware 1208 comprises electronic componentry and circuitry carried bycassette interface 1200 and specifically dedicated to the control of theelectronic components and circuitry of microfluidic chip 1030, 1130,1230, 1330, 1430 and cassette 1010. In the example illustrated, firmware1208 serves as part of a controller to control electric sensors 1138.

As schematically shown by FIG. 7, firmware 1208 comprises at least oneprinted circuit board 1210 which supports frequency source 1212, andimpedance extractor 1214 to receive first composite or base signals fromthe sensors 1138 and to extract impedance signals from the base signalsand a buffer 1216 to store the impedance signals as or until theimpedance signals are transmitted to mobile analyzer 1232. For example,in one implementation, impedance extractor 1214 performs analogquadrature amplitude modulation (QAM) which utilizes radiofrequency (RF)components to extract the frequency component out so that the actualshift in phase caused by impedance of the device under test (theparticular sensor 1138) may be utilized.

FIG. 21 is a schematic diagram of an example impedance sensing circuit1500 providing frequency source 1212 and impedance extractor 1214. Incircuit block 1510, signals are measured from the high and lowelectrodes in the microfluidic channel 1136 (the device under test(DUT)). In circuit block 1512, the circuitry converts the currentthrough the high low electrodes (device under test) to a voltage. Incircuit block 1514, the circuitry conditions the voltage signals so asto have a correct phase and amplitude before and after the mixer,respectively. In circuit block 1516, the circuitry breaks the input andoutput voltage signals into real and imaginary parts. In circuit block1518, the circuitry recovers each signal's amplitude. In circuit block1520, the circuitry filters out high-frequency signals. In circuit block1522, the circuitry converts the analog signals to digital signals wherethe digital signals are buffered by buffer 1216, such as with a fieldprogrammable gate array.

In one implementation, firmware 1208 comprises a field programmable gatearray which serves as a frequency source controller and the buffer 1216.In another implementation, firmware 1208 comprises anapplication-specific integrated circuit (ASIC) serving as a frequencysource controller, the impedance extractor 1214 and the buffer 1216. Ineach case, raw or base impedance signals from sensors 1138 are amplifiedand converted by an analog-to-digital converter prior to being used byeither the field programmable gate array or the ASIC. In implementationswhere firmware 1208 comprises a field programmable gate array or anASIC, the field programmable gate array or ASIC may additionally serveas a driver for other electronic components on micro-fluidic chip 1010such as microfluidic pumps 1160 (such as resistors), temperature sensors1175 and other electronic components upon the microfluidic chip.

Mobile analyzer 1232 comprises a mobile or portable electronic device toreceive data from cassette 1010. Mobile analyzer 1232 is releasably orremovably connected to cassette 1010 indirectly via cassette interface1200. Mobile analyzer 1232 performs varies functions using data receivedfrom cassette 1010. For example, in one implementation, mobile analyzer1232 stores the data. In the example illustrated, mobile analyzer 1232additionally manipulates or processes the data, displays the data andtransmits the data across a local area network or wide area network(network 1500) to a remote analyzer 1300 providing additional storageand processing.

In the example illustrated, mobile analyzer 1232 comprises electricalconnector 1502, power source 1504, display 1506, input 1508, processor1510, and memory 1512. In the example illustrated, electrical connector1502 is similar to electrical connectors 1206. In the exampleillustrated, electrical connector 1502 comprises a universal serial bus(USB) connector port to receive one end of a USB connector cord 1209,wherein the other end of the USB connector cord 1209 is connected to thecassette interface 1200. In other implementations, electrical connector1502 comprises a plurality of distinct electrical contact pads whichmake contact with corresponding electrical connectors of interface 1200,such as where one of interface 1200 and mobile analyzer 1232 directlyplug into the other of interface 1200 and mobile analyzer 1232. Inanother implementation, electrical connector 1206 comprises prongs orprong receiving receptacles. In still other implementations, electricalconnector 1502 may be omitted, where mobile analyzer 1232 and cassetteinterface 1200 each comprise a wireless communication device, utilizinginfrared, RF, BLUETOOTH®, or other wireless technologies forfacilitating wireless communication between interface 1200 and mobileanalyzer 1232.

Power source 1504 comprise a source of electrical power carried bymobile analyzer 1232 for supplying power to cassette interface 1200 andcassette 1010. Power source 1504 comprises various power controlelectronic componentry which control characteristics of the power(voltage, current) being supplied to the various electronic componentsof cassette interface 1200 and cassette 1010. Because power for bothcassette interface 1200 and cassette 1010 are supplied by mobileanalyzer 1232, the size, cost and complexity of cassette interface 1200and cassette 1010 are reduced. In other implementations, power forcassette 1010 and cassette interface 1200 are supplied by a batterylocated on cassette interface 1200. In yet another implementation, powerfor cassette 1010 is provided by a battery carried by cassette 1010 andpower for interface 1200 is supplied by a separate dedicated battery forcassette interface 1200.

Display 1506 comprises a monitor or screen by which data is visuallypresented. In one implementation, display 1506 facilitates apresentation of graphical plots based upon data received from cassette1010. In some implementations, display 1506 may be omitted or may bereplaced with other data communication elements such as light emittingdiodes, auditory devices are or other elements that indicate resultsbased upon signals or data received from cassette 1010.

Input 1508 comprises a user interface by which a person may inputcommands, selection or data to mobile analyzer 1232. In the exampleillustrated, input 1508 comprise a touch screen provided on display1506. In one implementation, input 1508 may additionally oralternatively utilize other input devices including, but are not limitedto, a keyboard, toggle switch, push button, slider bar, a touchpad, amouse, a microphone with associated speech recognition machine readableinstructions and the like. In one implementation, input 1506 facilitatesinput of different fluid tests or modes of a particular fluid testpursuant to prompts provided by an application program run on mobileanalyzer 1232.

Processor 1510 comprises at least one processing unit to generatecontrol signals controlling the operation of sensors 1138 as well as theacquisition of data from sensors 1138. Processor 1510 further outputscontrol signals controlling the operation of pumps 1160 and temperaturesensors 1175. In the example illustrated, processor 1510 furtheranalyzes data received from chip 230 to generate output that is storedin memory 1512, displayed on display 1506 and/or further transmittedacross network 1500 to remote analyzer 1300.

Memory 1512 comprises a non-transitory computer-readable mediumcontaining instructions for directing the operation of processor 1510.As schematically shown by FIG. 7, memory 1512 comprises or stores anapplication programming interface 1520 and application program 1522.Application programming interface 1520 comprises a library of routines,protocols and tools, which serve as building blocks, for carrying outvarious functions or tests using cassette 1010. Application programminginterface 1520 comprises machine readable instructions programmed logicthat accesses the library and assembles the “building blocks” or modulesto perform a selected one of various functions or tests using cassette1010. For example, in one implementation, application programminginterface 1520 comprises an application programming interface librarythat contains routines for directing the firmware 1208 to place electricsensors 1138 in selected operational states, such as through theapplication of different frequencies of alternating current. In theexample illustrated, the library also contains routines for directingfirmware 1208 to operate fluid pumps 1160 or dynamically adjustsoperation of such pumps 1160 or electric sensors 1138 in response to asensed temperature of the fluid being tested from temperature sensors1175. In one implementation, mobile analyzer 1232 comprises a pluralityof application programming interfaces 1520, each application programminginterface 1520 being specifically designed are dedicated to a particularoverall fluid or analyte test. For example, one application programminginterface 1520 may be directed to performing cytology tests. Anotherapplication program interface 1520 may be directed to performingcoagulation tests. In such implementations, the multiple applicationprogramming interfaces 1520 may share the library of routines, protocolsand tools.

Application programming interface 1520 facilitates testing of fluidsusing cassette 1010 under the direction of different applicationprograms. In other words, application programming interface 1520provides a universal programming or machine readable set of commands forfirmware 1208 that may be used by any of a variety of differentapplication programs. For example, a user of mobile analyzer 1232 isable to download or install any of a number of different applicationprograms, wherein each of the different application programs is designedto utilize the application program interface 1520 so as to carry outtests using cassette 1010. As noted above, firmware 1208 interfacesbetween application programming interface 1520 and the actual hardwareor electronic componentry found on the cassette 1010 and, in particular,microfluidic chip 1030, 1130, 1230, 1330, 1430.

Application program 1522 comprises an overarching machine readableinstructions contained in memory 1512 that facilitates user interactionwith application programming interface 1520 or the multiple applicationprogramming interfaces 1520 stored in memory 1512. Application program1522 presents output on display 1506 and receives input through input1508. Application program 1522 communicates with application programinterface 1520 in response to input received through input 1508. Forexample, in one implementation, a particular application program 1522presents graphical user interfaces on display 1506 prompting a user toselect which of a variety of different testing options are to be runusing cassette 1010. Based upon the selection, application program 1522interacts with a selected one of the application programming interfaces1520 to direct firmware 1208 to carry out the selected testing operationusing the electronic componentry of cassette 1010. Sensed valuesreceived from cassette 1010 using the selected testing operation arereceived by firmware 1208 and are processed by the selected applicationprogram interface 1520. The output of the application programminginterface 1520 is generic data, data that is formatted so as to beusable by any of a variety of different application programs.Application program 1522 presents the base generic data and/or performsadditional manipulation or processing of the base data to present finaloutput to the user on display 1506.

Although application programming interface 1520 is illustrated as beingstored in memory 1512 along with the application program 1522, in someimplementations, application programming interface 1520 is stored on aremote server or a remote computing device, wherein the applicationprogram 1522 on the mobile analyzer 1232 accesses the remote applicationprogramming interface 1520 across a local area network or a wide areanetwork (network 1500). In some implementations, application programminginterface 1520 is stored locally on memory 1512 while applicationprogram 1522 is remotely stored a remote server, such as server 1300,and accessed across a local area network or wide area network, such asnetwork 1500. In still other implementations, both applicationprogramming interface 1520 and application program 1522 are contained ona remote server or remote computing device and accessed across a localarea network or wide area network (sometimes referred to as cloudcomputing).

In the example illustrated, system 1000 facilitates a reduction in sizeof chip 1130 by utilizing multiplexer circuitry with the provision ofmultiplexer circuitry 1179 and associated multiplexer circuitry oninterface 1200 or mobile analyzer 1232, System 1000 further facilitatesthe reduction in size a chip 1130 through the appropriate allocation ofthe total transmission bandwidth of chip 1130 amongst the differentcontrolled devices of chip 1130, such as fluid sensors 1138, pumps 1140and temperature sensors 1175. Transmission bandwidth comprises the totalcapacity for the transmission of signals across and between connectorsof port 1204 and electrical contact pads 1177. Processor 1510 allocatesthe total transmission bandwidth by controlling the timing and rate atwhich control signals are output and sent across connectors of port 1204and connectors of electrical contact pads 1177 to the various controlleddevices fluid sensors 1138, pumps 1160 and temperature sensors 1175 aswell the timing and rate at which controlled devices are potted for datasignals or at which data is received from the controlled devices.Instead of equally apportioning such bandwidth amongst all thecontrolled devices 1138, 1160, 1175 or amongst the different types orclasses of controlled devices such as fluid sensors, temperature sensorsand pumps, processor 1510, following instructions contained memory 1512,differently allocates the transmission bandwidth amongst the differentcontrolled devices.

The different allocation of the total transmission bandwidth across thecontrolled devices 1138, 1160, 1175 is based upon the class ofcontrolled device or the generic function being performed by thedifferent controlled devices. For example, in one implementation, afirst portion of the total transmission bandwidth is allocated tosensors 1138, a second portion, different than the first portion, of thetotal transmission bandwidth is allocated to temperature sensors 1175and a third portion of the total transmission bandwidth, different fromthe first portion and a second portion, is allocated to pumps 1160. Inone implementation, the first portion of the total transmissionbandwidth allocated to sensors 1138 is uniformly or equally apportionedamongst the different individual sensors 1138, the second portion of thetotal transmission bandwidth allocated to temperature sensors 1175 isuniformly or equally apportioned amongst the different individualtemperature sensors 1175 and the third portion of the total transmissionbandwidth allotted to pumps 1160 is uniformly or equally apportionedamongst different individual controlled devices 1160.

In another implementation, the first portion, the second portion and thethird portion of the total transmission bandwidth are each non-uniformlyor unequally apportioned amongst the individual controlled devices ofeach class 1138, 1175, 1160 of the controlled devices. In oneimplementation, different fluid sensors 1138 operate differently, toform different tests upon a fluid sample. For example, in oneimplementation in which sensors 1138 comprise electric sensors, one offluid sensors 1138 is provided with a first frequency of alternatingcurrent while another of the fluid sensors 1138 is provided with asecond different frequency of alternating current such that the twosensors output signals that indicate different parameters arecharacteristics of the cells or particles being sensed. In such animplementation, processor 1510 allocates each of the different sensorswith a different percentage or portion of the total transmissionbandwidth based upon the different tests or based on the differentfrequencies of alternating current being applied to the differentsensors.

In one implementation, the allocation or apportionment of the totaltransmission bandwidth amongst individual controlled devices isadditionally based upon characteristics of the individual controlleddevice itself relative to other controlled devices in the same classdevices. For example, in one implementation, different sensors 1138 arelocated within differently sized constrictions. Such differently sizedconstrictions may result in a different concentration of cells orparticles in the fluid flowing across or through the constriction, adifferent frequency at which cells are particles flow through theconstriction or a different fluid flow rate across the constriction, thegeometry of the portion of the fluid channel 1136 in which the sensors1138 are located. In one implementation, those sensors 1138 locatedwithin constrictions having a greater fluid flow rate or a greaterfrequency at which cells or particles flow across such sensors areallocated a greater percentage of the total transmission bandwidthapportioned to the class of sensors as compared to other of such sensorsin the class that are located within constrictions having lower fluidflow rates or a lower frequency at which cells are particles flow acrosssuch sensors.

Likewise, in some implementations, different pumps 1160 are located indifferent microfluidic channels 1136, different portions of a channel1136 with different geometries. As a result, the fluid flow or pumpingdemands placed upon the different pumps 1160 may also differ. In suchimplementations, those particular pumps 1160 having greater pumpingdemands are allocated a greater percentage of the total transmissionbandwidth apportioned to the class of pumps as compared to other of suchpumps in the class that located within channels 1136 that have lesserpumping demands. For example, in one implementation, a pump which is tomove fluid through a longer microfluidic channel or a more tortuousmicrofluidic channel is provided with a greater percentage of the totaltransmission bandwidth to allow more frequent pulses and more frequentpumping as compared to another pump which is to move fluid through ashorter microfluidic channel or less tortuous microfluidic channel.

In one implementation, processor 1510 allocates a total transmissionbandwidth such that processor 1510 polls and receives data from each ofthe sensors 1138 at a frequency of at least once every 2 μs. In such animplementation, processor 1510 transmits pulses to pumps 1160,comprising resistors, at a frequency of at least once every 100 μs notmore frequent than once every 50 μs. In such an implementation,processor 1510 polls and receives data signals from temperature sensors1175 at a frequency of at least once every 10 ms and not more frequentthan once every 1 ms. In yet other implementations, other totaltransmission bandwidth allocations are employed.

In one implementation, processor 1510 flexibly or dynamically adjust thebandwidth allocation amongst the different controlled devices based uponsignal quality/resolution. For example, if a first amount of bandwidthallocated to impedance sensing by sensor 1138 is insufficient becausethe cells or other analyte are moving past sensor 1138 too fast suchthat the signal quality/resolution fails to satisfy a predeterminedstored signal quality/resolution threshold, processor 1510 mayautomatically or in response to suggesting a bandwidth allocationincrease to the user and receiving authorization from the user, increasethe bandwidth allocation to the particular sensor 1138. Conversely, if aparticular sensor 1138 has a lower fluid or cell flow rate due to thepumping rate, such that the allocated bandwidth exceeds the amount forachieving satisfactory signal quality/resolution, processor 1510automatically, or responses suggesting a bandwidth allocation decreaseof the user and receiving authorization from the user, decrease thebandwidth allocation to the particular sensor, wherein processor 1510allocates the now freed bandwidth to another one of sensors 1138.

In the example illustrated in which sensors 1138 comprise electricsensors, application program 1522 and application programming interface1520 cooperate to direct processor 1510 to control the frequency of thealternating current being applied to each of the sensors 1138 on chip1130. With respect to each individual sensor 1138, processor 1510 isdirected to apply different non-zero frequencies of alternating currentto an individual sensor 1138. In one implementation, processor 1510dynamically adjusts the frequency of alternating current being appliedto electric sensor 1138 based upon real time are ongoing performance ofelectric sensor 1138 to improve system performance. For example, in oneimplementation, controller 1510 outputs control signals that apply afirst non-zero frequency of alternating current to a selected electricsensor 1138. Based upon signals received from the selected electricsensor 1138 during the application of the first non-zero frequency ofalternating current, controller 1510 adjusts the value of thesubsequently applied frequency of alternating current applied toelectric sensor 1138. Processor 1510 outputs control signals such thatfrequency source 1212 applies a second non-zero frequency of alternatingcurrent to the selected electric sensor 1138, wherein a value of thesecond non-zero frequency of alternating current applied by frequencysource 1212 to the selected electric sensor 1138 is based upon signalsreceived from the electric sensor 1138 during the application of thefirst non-zero frequency of alternating current.

In one implementation, processor 1510 selectively applies differentnon-zero frequencies of alternating current to perform different testsupon the fluid sample. As a result of processor 1510 causing frequencysource 1212 to apply different non-zero frequencies of alternatingcurrent to the electric sensor 1138, the electric sensor 1138 performsdifferent tests, outputting different signals that may indicatedifferent properties or characteristics of the fluid, or cells containedtherein. Such different tests are performed on a single fluid sample ona single fluid testing platform without the fluid sample having to betransferred from one testing device to another. As a result, integritythe fluid sample is maintained, the cost and complexity of performingthe multiple different tests is reduced and the amount of potentiallybio-hazardous waste is also reduced.

In one implementation, application program 1522 directs processor 1510to prompt a user for selection of a particular fluid test to be carriedout by system 1000. In one implementation, application program 1522causes processor 1510 to display on display 1506, for selection by user,different names of different tests or the characteristics orcell/particle parameters for selection. For example, processor 1510 maydisplay cell count, cell size or some other parameter for selection bythe user using input 1508.

In one implementation, prior to prompting a user for selection of aparticular fluid test, application program 1522 to direct processor 1510to carry out a check with the fluid testing device providing electricsensor 1138 to determine or identify what fluid tests or what frequencyranges are available or for which the fluid testing device is capable ofproviding. In such an implementation, program 1522 automaticallyeliminates those fluid tests that cannot be provided by the particularcassette 1010 from the list or menu of possible choices of fluid testsbeing presented to the user. In yet another implementation, applicationprogram 1522 presents a full menu of fluid tests, but notifies the userof those particular fluid tests that are not presently available orselectable given the current cassette 1010 connected to analyzer 1232.

Based upon the received selection for the fluid test to be carried out,processor 1510, following instructions contained in application program1522, selects a scan range of frequencies of alternating current whichis to be crossed or covered during testing with the electric sensor1138. The scan range is a range across which multiple differentfrequency of alternating current are to be applied to electric sensor 38according to a predefined scan profile. The scan range identifies theendpoints for a series of different frequencies of alternating currentto be applied to electric sensor 1138 during testing. In oneimplementation, a scan range of 1 kHz to 10 MHz is applied to a sensor1138.

The scan profile indicates the specific AC frequency values between theendpoints of the range and their timing of their application to electricsensor 1138. For example, a scan profile may comprise a continuousuninterrupted series of AC frequency values between the endpoints of thescan range. Alternatively, a scan profile may comprise a series ofintermittent AC frequency values between the endpoints of the scanrange. The number, time interval spacing between different frequenciesand/or the incrementing of the frequency values themselves may beuniform or non-uniform in different scan profiles.

In one implementation or user selected mode of operation, processor 1510carries out the identified scan range and scan profile to identify afrequency that provides the greatest signal-to-noise ratio for theparticular testing carried out. After a fluid sample is added andportions of the fluid sample have reached a sense zone and have beendetected at the sense zone, the associate pump 1160 is deactivated suchthat the analyte (cell or particle) is static or stationary in the sensezone of the adjacent sensor 1138. At this time, processor 1510 carriesout the scan. During the scan, the frequency of alternating currentapplied to the particular sensor 1138 which results in the greatestsignal-to-noise ratio is identified by processor 1510. Thereafter, pump1160 which pumps fluid across the particular sensor 1138 is once againactivated and the fluid sample is tested using the sensor 1138 with theidentified frequency of alternating current being applied to the sensor1138. In another implementation, a predetermined nominal frequency ofalternating current is identified based upon the particular fluid testbeing performed, wherein multiple frequencies around the nominalfrequency are applied to sensor 1138.

In one implementation or user selected mode of operation, processor 1510identifies the particular range most suited for the fluid test selectedby the, wherein the scan profile is a default profile, being the samefor each of the different ranges. In another implementation or userselected mode of operation, processor 1510 automatically identifies theparticular scan range most suited for the selected fluid test, whereinthe user is prompted to select a scan profile. In another implementationor user selected mode of operation, processor 1510, followinginstructions provided by application program 1522, automaticallyidentifies not only the most appropriate range for the particular fluidtest selected by the user, but also the particular scan profile for theparticular range for the particular fluid test selected by the user. Instill another implementation or user selectable mode of operation, theuser is prompted to select a particular scan profile, wherein processor1510 identifies the most appropriate scan range, given the selected scanprofile for the particular selected fluid test. In one implementation,memory 1512, or a remote memory, such as memory 1604, contains a lookuptable which identifies different scan ranges in different scan profilesfor different available or selectable fluid tests or fluid/cell/particleparameters for which a fluid test may be performed.

One implementation in which sensors 1138 comprise electric sensors,application program interface 1520 and application program 1522cooperate to direct processor 1510 to apply different frequencies ofalternating current to different sensors 1138 on the same microfluidicchip 1130 of cassette 1010. In one implementation, processor 1510provides user selection of the different non-zero frequencies ofalternating current applied to the different electric sensors 38.Because processor 1510 directs frequency source 1512 applies differentnon-zero frequencies of alternating current to the different electricsensors 1138, the different electric sensors 1138 perform differenttests, outputting different signals that may indicate differentproperties or characteristics of the fluid, or cells contained therein.Such different tests are performed on a single fluid sample on a singlefluid testing platform without the fluid sample having to be transferredfrom one testing device to another. As a result, integrity the fluidsample is maintained, the cost and complexity of performing the multipledifferent tests is reduced and the amount of potentially biohazardouswaste is also reduced.

In the example illustrated, application program 1522 and applicationprogramming interface 1520 further cooperate to direct processor 1510 toregulate the temperature of the fluid sample being tested by cassette1010. Application program 1522, application programming interface 1520and processor 1510 serve as a controller that facilitates thedual-purpose functioning of resistors serving as pumps 1160 to achieveboth fluid pumping and fluid temperature regulation. In particular,processor 1510 actuates resistor to a fluid pumping state by outputtingcontrol signals causing a sufficient amount of electrical current topass through pump 1160 such that resistor of pump 1160 heats adjacentfluid within a microfluidic channel 1136, 1236, 1336, 1436 to atemperature above a nucleation energy of the fluid. As a result, theadjacent fluid is vaporized, creating a vapor bubble having a volumelarger than the volume of the fluid from which the vapor bubble wasformed. This larger volume serves to push the remaining fluid that wasnot vaporized within the channel to move the fluid across sensor 1138 orthe multiple senses 1138. Upon collapse of the vapor bubble, fluid isdrawn from microfluidic reservoir 1134 into the channel to occupy theprevious volume of the collapsed paper bubble. Processor 1510 actuatesthe resistor of pump 1160 to the pumping state in an intermittent orperiodic fashion. In one implementation, processor 1510 actuates theresistor of pump 1160 to the pumping state in a periodic fashion suchthat the fluid within the microfluidic channel is continuously moving orcontinuously circulating.

During those periods of time that the resistor of pump 1160 is not beingactuated to the pumping state, to a temperature above the nucleationenergy of the fluid, processor 1510 uses the same resistor of pump 1160to regulate the temperature of the fluid for at least those periods thetime that the fluid is extending adjacent to or opposite to sensor 1138and is being sensed by sensor 1138. During those periods the time thatresistor 1160 is not in the pumping state, processor 1510 selectivelyactuates the resistor of pump 1160 to a temperature regulation state inwhich adjacent fluid is heated without being vaporized. Processor 1510actuates resistor of pump 1160 to a fluid heating or temperatureregulating state by outputting control signals causing a sufficientamount of electrical current to pass through resistor of pump 1160 suchthat the resistor of pump 1160 heats adjacent fluid within themicrofluidic channel to a temperature below a nucleation energy of thefluid, without vaporizing the adjacent fluid. For example, in oneimplementation, controller actuates resistor to an operational statesuch that the temperature of adjacent fluid rises to a first temperaturebelow a nucleation energy of the fluid and then maintains or adjusts theoperational state such that the temperature of the adjacent fluid ismaintained constant or constantly within a predefined range oftemperatures that is below the nucleation energy. In contrast, when theresistor of pump 1160 is being actuated to a pumping state, pump 1160 isin an operational state such that the temperature of fluid adjacent theresistor of pump 1160 is not maintained at a constant temperature orconstantly within a predefined range of temperatures (both rising andfalling within the predefined range of temperatures), but rapidly andcontinuously increases or ramps up to a temperature above the nucleationenergy of the fluid.

In one implementation, processor 1510 controls the supply of electricalcurrent across the resistor of pump 1160 such that the resistor operatesin a binary manner when in the temperature regulating state (thetemperature of the adjacent fluid is not heated to a temperature aboveits nucleation energy). In implementations where the resistor of pump1160 operates in a binary manner in the temperature regulating state,the resistor of pump 1160 is either “on” or “off”. When the resistor ofpump 1160 is “on”, a predetermined amount of electrical current ispassed through the resistor of pump 1160 such the resistor of pump 1160emits a predetermined amount of heat at a predetermined rate. When theresistor of pump 1160 is “off”, electrical current is not passed throughthe resistor such that resistor does not generate or emit any additionalheat. In such a binary temperature regulating mode of operation,processor 1510 controls the amount of heat applied to the fluid withinmy clinic channel by selectively switching the resistor of pump 1160between the “on” and “off” states.

In another implementation, processor 1510 controls or sets the resistorof pump 1160 at one of a plurality of different “on” operational stateswhen in the temperature regulation state. As a result, processor 1510selectively varies the rate at which heat is generated and emitted bythe resistor of pump 1160, the heat emitting rate being selected fromamongst a plurality of different available non-zero heat emitting rates.For example, in one implementation, Processor 1510 selectively varies orcontrols a rate at which heat is amended by the resistor of pump 1160 byadjusting a characteristic of pump 1160. Examples of a characteristic ofthe resistor of pump 1160 (other than an on-off state) that may beadjusted include, but are not limited to, adjusting a non-zero pulsefrequency, a voltage and a pulse width of electrical current suppliedacross the resistor. In one implementation, Processor 1510 selectivelyadjusts multiple different characteristics to control or regulate therate at which heat is being emitted by the resistor of pump 1160.

In one user selectable operational mode, processor 1510, followinginstructions from application programming interface 1520 and applicationprogram 52, selectively actuates the resistor of pump 1160 to thetemperature regulating state to maintain a constant temperature of thefluid below the nucleation energy of the fluid or to maintain atemperature of the fluid constantly within a predefined range oftemperatures below the nucleation energy in the fluid according to apredefined or predetermined schedule. In one implementation, thepredetermined schedule is a predetermined periodic or time schedule. Forexample, through historical data collection regarding particulartemperature characteristics of fluid testing system 1000, it may havebeen discovered that the temperature of a particular fluid sample influid testing system 1000 undergoes changes in temperature in apredictable manner or pattern, depending upon factors such as the typeof fluid being tested, the rate/frequency at which the resistor of pump1160 is being actuated to the pumping state, the amount of heat emittedby temperature regulator 60 during a pumping cycle in which anindividual vapor bubble is created, the thermal properties, thermalconductivity, of various components of fluid testing system 1000, thespacing of the resistor of pump 1160 and sensor 1138, the initialtemperature of the fluid sample when initially deposited into sampleinput port 1018 or into testing system 1000 and the like. Based upon theprior discovered predictable manner or pattern at which the fluid sampleundergoes changes in temperature or temperature losses in system 1000,Processor 1510 outputs control signals selectively controlling when theresistor of pump 1160 is either on or off as described above and/orselectively adjusting the characteristic of the resistor of pump 1160 ormultiple pumps 1160 when the resistor of pump 1160 is in the “on” stateso as to adapt to the discovered pattern of temperature changes or lossand so as to maintain a constant temperature of the fluid below thenucleation energy of the fluid or to maintain a temperature of the fluidconstantly within a predefined range of temperatures below thenucleation energy. In such an implementation, the predefined periodictiming schedule at which processor 1510 actuates the resistor of pump1160 to a temperature regulation state and at which processor 1510selectively adjusts an operational characteristic of resistor to adjustthe heat emitting rate of the resistor of pump 1160 is stored in memory1512 or is programmed as part of an integrated circuit, such as anapplication-specific integrated circuit.

In one implementation, the predefined timing schedule at which processor1510 actuates pump 1160 to the temperature regulating state and at whichprocessor 1510 adjusts the operational state of pump 1160 in thetemperature regulating state is based upon or is triggered by insertionof a fluid sample into testing system 1000. In another implementation,the predefined timing schedule is based upon or triggered by an eventassociated with the pumping of the fluid sample by the resistor of pump1160. In yet another implementation, the predefined timing schedule isbased upon or triggered by the output of signals or data from sensor1138 or the schedule or frequency at which sensor 1138 is to sense thefluid and output data.

In another user selectable mode of operation, processor 1510 selectivelyactuates the resistor of pump 1160 to the temperature regulating stateand selectively actuates the resistor of pump 1160 to differentoperational states while in the temperature regulating state based uponsignals from temperature sensors 1175 indicating the temperature of thefluid being tested. In one implementation, Processor 1510 switches theresistor of pump 1160 between the pumping state and the temperatureregulating state based upon received signals received from temperaturesensors 1175 indicating a temperature of the fluid being tested. In oneimplementation, processor 1510 determines the temperature the fluidbeing tested based upon such signals. In one implementation, processor1510 operates in a closed loop manner in which processor 1510continuously or periodically adjusts the operational characteristic ofthe resistor of pump 1160 in the temperature regulating state based uponfluid temperature indicating signals being continuously or periodicallyreceived from a temperature sensor 1175 or more than one temperaturesensor 1175.

In one implementation, processor 1510 correlates or indexes the value ofthe signals received from temperature sensors 1175 to correspondingoperational states of the resistor of pump 1160 and the particular timesat which such operational states of the resistor were initiated, thetimes which such operational state of the resistor were ended and/or theduration of such operational states of the resistor of pump 1160. Insuch an implementation, processor 1510 stores the indexed fluidtemperature indicating signals and their associated resistor operationalstate information. Using the stored indexed information, processor 1510determines or identifies a current relationship between differentoperational states of the resistor pump 1160 and the resulting change intemperature of the fluid within the microphone a channel. As a result,processor 1510 identifies how the temperature of the particular fluidsample or a particular type of fluid within the microfluidic channelrespond to changes in the operational state of the resistor pump 1160 inthe temperature regulation state. In one implementation, processor 1510presents the displayed information to allow an operator to adjustoperation of testing system 1000 to account for aging of the componentsof testing system 1000 or other factors which may be affecting how fluidresponse to changes in operational characteristics of the resistor ofpump 1160. In another implementation, processor 1510 automaticallyadjusts how it controls the operation of the resistor of pump 1160 inthe temperature regulating state based upon the identified temperatureresponses to the different operational state of the resistor. Forexample, in one implementation, processor 1510 adjusts the predeterminedschedule at which the resistor of pump 1160 is actuated between the “on”and “off” states or is actuated between different “on” operationalstates based upon the identified and stored thermal responserelationship between the fluid sample and the resistor. In anotherimplementation, processor 1510 adjusts the formula controlling howprocessor 1510 responds in real time to temperature signals receivedfrom temperature sensors 1175.

Although, in the example illustrated, mobile analyzer 1232 isillustrated as comprising a tablet computer, in other implementations,mobile analyzer 1232 comprises a smart phone or laptop or notebookcomputer. In yet other implementations, mobile analyzer 1232 is replacedwith a stationary computing device, such as a desktop computer orall-in-one computer.

Remote analyzer 1300 comprises a computing device remotely located withrespect to mobile analyzer 1232. Remote analyzer 1300 is accessibleacross network 1500. Remote analyzer 1300 provides additional processingpower/speed, additional data storage, data resources and, in somecircumstances, application or program updates. Remote analyzer 1300(schematically shown) comprises communication interface 1600, processor1602 and memory 1604. Communication interface 1600 comprise atransmitter that facilitates communication between remote analyzer 1300and mobile analyzer 1232 across network 1500. Processor 1602 comprises aprocessing unit that carries out instructions contained in memory 1604.Memory 1604 comprises a non-transitory-computer-readable mediumcontaining machine readable instructions, code, program logic or logicencodings that direct the operation of processor 1602. Memory 1604further to store data or results from the fluid testing performed bysystem 1000.

As further shown by FIG. 7, memory 1512 additionally comprises buffermodule 1530, data processing module 1532 and plotting module 1534.Modules 1530, 1532 and 1534 comprise programs, routines alike whichcooperate to direct processor 1510 to carry out and multi-threaded fluidparameter processing method as diagrammed in FIG. 22. FIG. 22illustrates and describes the reception and processing of a single datareceiver thread 1704 by processor 1510. In one implementation, themulti-threaded fluid parameter processing method 1700 is concurrentlyperformed by processor 1510 for each of multiple concurrent datareceiver threads in which multiple data sets are concurrently beingreceived. For example, in one implementation, processor 1510concurrently receives data signals representing sets of data regardingelectrical parameters, thermal parameters and optical parameters. Foreach data set or series of signals for different parameters beingreceived, processor 1510 concurrently carries out method 1700. All ofsuch data sets being concurrently received, buffered, analyzed and thenplotted or otherwise presented or displayed on mobile analyzer 1232.

During testing of a fluid sample, such as a blood sample, processor 1510continuously executes a data receiver thread 1704 in which signalsindicating at least one fluid characteristic are received by processor1510. In one implementation, the signals received by processor 1510pursuant to the data receiver thread 1704 comprise foundational data.For purposes of this disclosure, the term “foundational data”,“foundational signals”, “foundational fluid parameter data” or“foundational fluid parameter signals” refers to signals from fluidsensor 1138 that have solely undergone modifications to facilitate useof such signals such as amplification, noise filtering or removal,analog-to-digital conversion and, in the case of impedance signals,quadrature amplitude modulation (QAM). QAM utilizes radiofrequency (RF)components to extract the frequency component out so that the actualshift in phase caused by impedance of the device under test (theparticular sensor 1138) is identified.

In one implementation, the signals continuously received by processor1510 during execution of the data receiver thread 1704 compriseelectrical impedance signals indicating changes in electrical impedanceresulting from the flow of the fluid through art across an electricfield region. The signals continuously received by processor 1510 duringexecution of the data receiver thread 1704 comprise foundational data,meaning that such signals have undergone various modifications tofacilitate subsequent use and processing of such signals as describedabove. In one implementation, data receiver thread 1704, carried out byprocessor 1510, receives the foundational impedance data or foundationalimpedance signals at a rate of at least 500 kHz.

During reception of the foundational fluid parameter signals under thedata receiver thread 1704, buffer module 1530 directs processor 1510 torepeatedly buffer or temporarily store a predetermined time quantity offoundational signals. In the example illustrated, buffer module 1530directs processor 1510 to repeatedly buffer or temporarily store in amemory, such as memory 1512 or another memory, all of the foundationalfluid parameter signals received during a one second interval or periodof time. In other implementations, the predetermined time quantity offoundational signals comprises all the foundational fluid parametersignals received during a shorter or during a longer period of time.

Upon completion of the buffering of each predetermined time quantity ofsignals, data processing module 1532 directs processor 1510 to initiateand cam/out a data processing thread that executes on each of thefoundational fluid parameter signals buffered in the associated and justcompleted time quantity of foundational fluid parameter signals. Asdiagrammed in the example of FIG. 3, after the foundational fluidparameter signals, such as impedance signals, have been received fromcassette interface 1200 for the first predetermined period of time 1720and buffered, data processing module 1532 directs processor 1510, attime 1722, to initiate a first data processing thread 724 during whicheach of the foundational fluid parameter signals received during periodof time 1720 are processed or analyzed. For purposes of this disclosure,the terms “process” or “analyze” with reference to foundational fluidparameter signals refers to additional manipulation of the foundationalfluid parameter signals through the application of formulas and thelike, beyond acts such as amplification, noise reduction or removal ormodulation, to determine or estimate actual properties of the fluidbeing tested. For example, processing or analyzing foundational fluidparameter signals comprises using such signals to estimate or determinea number of individual cells in a fluid at a time or during a particularperiod of time, or to estimate or determine other physical properties ofthe cells or of the fluid itself, such as the size of cells or the like.

Likewise, after fluid parameter signals from fluid testing device havebeen received and buffered for the second predetermined period of time1726, which consecutively follows the first period of time 1720, dataprocessing module 1532 directs processor 1510 at time 1728, to initiatea second data processing thread 1730 during which each of thefoundational fluid parameter signals received during the period of time1726 are processed or analyzed. As indicated in FIG. 22 and theillustrated data processing thread 1732 (data processing thread M), thedescribed cycle of buffering a predetermined time quantity of signalsand then, upon the expiration of the time quantity or period of time,initiating an associated data thread to act upon or process the signalsreceived during the period of time is continuously repeated as the datareceiver thread 1704 continues to receive fluid parameter data signalsfrom cassette interface 1200.

Upon completion of each data processing thread, the processed signals ordata results are passed or transferred to a data plotting thread 1736 asdiagrammed in FIG. 22. In the example illustrated, upon completion ofprocessing of the fluid parameter signals received during the period oftime 1720 at time 1740, the results or process data from such processingor analysis are transmitted to data plotting thread 1736, wherein theresults are incorporated into the ongoing plotting being carried out bydata plotting thread 1736 under the direction of plotting module 1534.Likewise, upon completion of the processing of the fluid parametersignals that were received during the period of time 1726 at time 1742,the results or process data from such processing or analysis aretransmitted to data plotting thread 1736, wherein the results areincorporated into the ongoing plot being carried out by data plottingthread 1736 under the direction of plotting module 1534.

As shown by FIG. 22, each data processing thread 1724, 1730 consumes amaximum amount of time to process the predetermined time quantity offoundational signals, wherein this maximum amount of time to processpredetermined time quantity of signals is greater than the predeterminedtime quantity itself. As shown by FIG. 22, by multithreading theprocessing of fluid parameter signals received during fluid testing,mobile analyzer 1232 serves as a mobile analyzer by processing themultiple signals being received in real time, in parallel, facilitatingthe plotting of the results by plotting module 1534 in real time,avoiding a reducing any lengthy delays. Processor 1510, following theinstructions contained in plotting module 1534, displays the results ofthe data plotting thread on display 1506 while the data receiver thread1704 is continuing to receive and buffer fluid parameter signals.

Processor 1510 further transmits data produced by data processingthreads 1724, 1730, . . . 1732 across network 1500 to remote analyzer1300. In one implementation, processor 1510 transmits the data, whichcomprises the results of the processing carried out in the associateddata processing thread, to remote analyzer 1300 in a continuous fashionas the results of the data processing thread are generated during theexecution of the data processing thread. For example, results generatedat time 1740 during execution a data processing thread 1740 areimmediately transferred to remote analyzer 1300 rather than waitinguntil time 1742 at which data processing thread 1730 has ended. Inanother implementation, 1510 transmits the data as a batch of data afterthe particular data processing thread has been completed or has ended.For example, in one implementation, processor 1510 transmits the all theresults of data processing thread 1724 as a batch to remote analyzer1300 at time 1740, the same time that such results are transmitted todata plotting thread 1736.

Processor 1602 of remote analyzer 1300, following instructions providedby memory 1604, analyzes the received data. Processor 1602 transmits theresults of its analysis, the analyzed data, back to mobile analyzer1232. Mobile analyzer 1232 displays or otherwise presents the analyzeddata received from remote analyzer 1300 on display 1506 or communicatesresults in other fashions, whether visibly or audibly.

In one implementation, remote analyzer 1300 receives data from mobileanalyzer 1232 that has already been analyzed or processed by analyzer1232, wherein mobile analyzer 1232 has already performed or carried outsome forms of manipulation of the foundational fluid parameter signalsor foundational fluid parameter data received from cassette 1010. Forexample, in one implementation, mobile analyzer 1232 performs a firstlevel of analysis or processing on the foundational fluid parameter dataare signals. For example, impedance analysis is done on the mobileanalyzer which would give the number of cells passing through thesensor. The results of such processing are then transmitted to remoteanalyzer 1300. Remote analyzer 1300 applies a second level of analysisor processing on the results received from mobile analyzer 1232. Thesecond level of analysis may comprise application of additionalformulas, statistical computations or the like to the results receivedfrom mobile analyzer 1232. Remote analyzer 1300 carries out additional,more complex and more time-consuming or processing power burdensomeprocessing or analysis of the data that has already undergone some formof processing or analysis at mobile analyzer 1232. Examples of suchadditional analysis that is carried out at remote analyzer 1300includes, but is not limited to, coagulation rate calculation and alsoanalytics on data collected from various mobile analyzers to find trendsand provide meaningful suggestions. For example, remote analyzer 1232may aggregate data from several patients over a large geographic area tofacilitate epidemiological studies and identify the spread of disease.

Although the present disclosure has been described with reference toexample implementations, workers skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the claimed subject matter. For example, although differentexample implementations may have been described as including featuresproviding benefits, it is contemplated that the described features maybe interchanged with one another or alternatively be combined with oneanother in the described example implementations or in other alternativeimplementations. Because the technology of the present disclosure isrelatively complex, not all changes in the technology are foreseeable.The present disclosure described with reference to the example and setforth in the following claims is manifestly intended to be as broad aspossible. For example, unless specifically otherwise noted, the claimsreciting a single particular element also encompass a plurality of suchparticular elements.

What is claimed is:
 1. A fluid testing cassette comprising: a chipcomprising: a microfluidic reservoir; a microfluidic channel extendingfrom the microfluidic reservoir and having: a constriction having awidth of no greater than 30 μm; a cross-sectional area that is smallerthan both adjacent regions of the microfluidic channel; a first portionextending from the microfluidic reservoir and containing a thermalresistor; and multiple additional portions branching from the firstportion back to the microfluidic reservoir; and a micro-fabricatedintegrated sensor within the constriction.
 2. The fluid testing cassetteof claim 1 further comprising a cassette body supporting the chip, thecassette body comprising a sample input port connected to themicrofluidic reservoir.
 3. The fluid testing cassette of claim 2 furthercomprising: a reagent within the sample input port; and a removablepackaging completely enclosing the cassette body and the chip.
 4. Thefluid testing cassette of claim 2 further comprising a residence passageextending tortuously downward from the sample input port to microfluidicreservoir.
 5. The fluid testing cassette of claim 2, wherein thecassette body further comprises a discharge reservoir to receive fluidthat has passed through the chip.
 6. The fluid testing cassette of claim5, wherein the chip further comprises: a nozzle connecting themicrofluidic channel to the discharge reservoir; and a thermal resistorto expel fluid through the nozzle into the discharge reservoir.
 7. Thefluid testing cassette of claim 1, wherein the microfluidic channelcomprises: a second portion branching from the first portion back to themicrofluidic reservoir, the second portion having the constrictioncontaining the micro-fabricated integrated sensor; and a third portionbranching from the first portion back to the microfluidic reservoir, thethird portion having a third constriction containing a thirdmicro-fabricated integrated sensor.
 8. The fluid testing cassette ofclaim 7, wherein the first portion has an inlet from the microfluidicreservoir of a first width, wherein the second portion has an outlet tothe reservoir of a second width greater than the first width and whereinthe third portion has an outlet to the reservoir of a third widthgreater than the first width.
 9. The fluid testing cassette of claim 1,wherein the microfluidic channel comprises a second constrictioncontaining a second micro-fabricated integrated sensor, wherein theconstriction has a first width and wherein the second constriction has asecond width different than the first width.
 10. The fluid testingcassette of claim 1 further comprising a thermal resistor within themicrofluidic channel to pump fluid through the microfluidic channel,wherein: the thermal resistor has a length along the microfluidicchannel; the micro-fabricated integrated sensor is spaced from thethermal resistor along the microfluidic channel by a spacing of at leastthe length; and the thermal resistor is spaced from the microfluidicreservoir along the microfluidic channel by a spacing of at least thelength.
 11. The fluid testing cassette of claim 1, wherein themicro-fabricated integrated sensor has a length along the microfluidicchannel, wherein the microfluidic channel has a second constriction,wherein the chip further comprises a second micro-fabricated integratedsensor within the second constriction and wherein the secondmicro-fabricated integrated sensor is spaced from the micro-fabricatedintegrated sensor by a distance of at least twice the length.
 12. Afluid testing cassette comprising: a sample input port to receive anddirect a fluid sample to be tested to a microfluidic channel; a sidechamber to supply a fluid reagent to the sample input port; themicrofluidic channel comprising: a first portion extending from themicrofluidic reservoir and containing a thermal resistor in aconstriction; and at least one additional portion branching from thefirst portion back to the microfluidic reservoir; per each of theadditional portions, a micro-fabricated integrated sensor within aconstriction; a discharge reservoir; a nozzle connecting themicrofluidic channel to the discharge reservoir; and a thermal resistorwithin the microfluidic channel to expel fluid in the microfluidicchannel into the discharge reservoir.
 13. The fluid testing cassette ofclaim 7, wherein the second portion and the third portion branch off ofopposite sides of the first portion.
 14. The fluid testing cassette ofclaim 7, wherein the second portion and the third portion have differentdimensions.
 15. The fluid testing cassette of claim 12, wherein thesample input port comprises an open mouth to receive the fluid sample.16. The fluid testing cassette of claim 12, wherein the sample inputport comprises a membrane to cover the sample input port.
 17. The fluidtesting cassette of claim 12, wherein the discharge reservoir extendsbelow the sample input port.
 18. The fluid testing cassette of claim 12,wherein: the at least one additional portion comprises a second portionbranching from the first portion back to the microfluidic reservoir; andthe microfluidic channel comprises a third portion branching from thesecond portion and returning to the second portion.
 19. A fluid testingcassette comprising: a cassette body; a sample input port to receive anddirect a fluid sample to be tested to a microfluidic chip; a sidechamber to supply a fluid reagent to the sample input port; a flexiblediaphragm over the side chamber to squeeze reagent into the sample inputport upon depression of the flexible diaphragm; the microfluidic chip,wherein the microfluidic chip comprises: a microfluidic reservoir; amicrofluidic channel extending from the microfluidic reservoircomprising: a first U-shaped portion extending from the microfluidicreservoir and containing a thermal resistor; multiple additionalU-shaped portions branching from the first portion back to themicrofluidic reservoir; and per each of the multiple additional U-shapedportions, a constriction having: a cross-sectional area that is smallerthan both adjacent regions; and columns projecting between walls of theportion; a micro-fabricated integrated sensor within each constriction;a discharge reservoir enclosed within the cassette body; a nozzleconnecting the microfluidic channel to the discharge reservoir; adischarge passage extending from the nozzle towards the dischargereservoir to inhibit reverse backflow; and a thermal resistor within themicrofluidic channel to expel fluid in the microfluidic channel into thedischarge reservoir.
 20. The fluid testing cassette of claim 19, whereinthe sample input port comprises a mouth formed on an elevated mound, atop surface of the elevated mound concave to match a surface of afinger.